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chapter 2

Physics

The Dazzler system is an Acousto-Optic Programmable Dispersive Filter (AOPDF). This chap-
ter briefly describes the physical principles of the device. All the figures illustrate the standard
AOPDFs configuration based on a Paratellurite crystal (TeO2).

2.1

AOPDF principle

In an AOPDF, the pulse shaping mechanism arises from a copropagative interaction between
a polychromatic acoustic wave and a polychromatic optical wave in a birefringent crystal with
acousto-optic properties. When the right physical conditions are met (the so-called phase-
matching conditions), the input optical and acoustic beams interact and give rise to a new
optical beam, which is referred to as the diffracted beam. Section

2.1.1

describes the phase-

matching conditions whereas section

2.1.2

details one special feature of the acousto-optic in-

teraction in an AOPDF: the collinearity in terms of Poynting vectors. Section

2.1.3

gives more

details on the pulse-shaping mechanism.

2.1.1

Phase-matching conditions

As for all three-wave mixing processes, the phase-matching condition for monochromatic plane
waves is defined by two conditions:

•

wave-vector conservation (momentum conservation)

•

frequency conservation (quantum energy conservation)

Mathematically, these conditions can be expressed as:

(

~k

diff

(

ω

opt,diff

) =

~k

in

(

ω

opt,in

) +

~k

ac

(

ω

ac

)

ω

opt,diff

=

ω

opt,in

+

ω

ac

(2.1)

where (

~k

diff

, ω

opt,diff

), (

~k

in

, ω

opt,in

) and (

~k

ac

, ω

ac

) stand for the wave-vectors and angular frequen-

cies of the optical diffracted beam, optical input beam and acoustic beam respectively.
For the standard AOPDFs, based on TeO

2

, the input optical beam is usually

ordinary

polarized,

the diffracted beam is

extraordinary polarized

and the acoustic beam is a shear wave.

Since the velocity of sound in crystals is much lower than the velocity of light, the acoustic
frequency is completely negligible with respect to that of light (

ω

ac

ω

opt

) so that the phase-

matching condition reads finally:

6

Содержание DAZZLER

Страница 1: ...DAZZLERTM system manual Part I installation operation V3 00 8th April 2019 i i 94 ...

Страница 2: ...to drive n points 11 2 2 6 Convolution with an acoustical linear chirp 12 2 2 7 Maximal pulse shaping capability 12 2 2 8 Crystal dispersion compensation 12 2 2 9 Beam orientations 13 2 3 Formulæ 13 3 Installation setup 15 3 1 Connections 15 3 1 1 Connecting the unit and starting the software 15 3 1 2 Define the general settings 16 3 1 3 Define the waveform combination options 16 3 1 4 Define the ...

Страница 3: ...vious mode 32 4 3 3 Influence of Trigger Delay limits 32 4 3 4 No Delay 33 4 3 5 High repetition rate 34 5 Software Operation 36 5 1 Front panel 36 5 1 1 Blue area power constant gain zero load wave in memory 37 5 1 2 Orange area spectral amplitude control 38 5 1 3 Green Area spectral phase control 38 5 1 4 Grey Area Waveform Combination 39 5 1 5 Graphs 39 5 1 6 Loaded waves 40 5 1 7 Machine contr...

Страница 4: ...ling 64 6 2 4 File C dazzler paths txt 64 6 2 5 Star commands 64 6 2 6 Wave file inclusion in request wave 66 6 3 Dazzler Network Remote Toolkit 67 6 3 1 Scope and Principle 67 6 3 2 Walk through of a simple code 67 7 Cabling tips 70 7 1 Basic principles 70 7 1 1 Ground plane layout crossings 70 7 1 2 Use of EMI ferrites 71 7 1 3 Termination of signals 71 7 2 USB cable 71 7 3 Practical examples 73...

Страница 5: ...RF cycles description 81 8 6 1 Single cycles 81 8 6 2 Continuous mode 84 8 6 3 Alternate mode 84 8 7 Output signals S1 S4 86 8 7 1 Output signal S1 86 8 7 2 Output signal S2 86 8 7 3 Output signal list 87 8 7 4 Descriptions of selectable signals 87 8 8 Specifications 92 Bibliography 92 V3 00 8th April 2019 v v 94 ...

Страница 6: ...ight Equivalent spectrum and time graphs 26 4 3 Incorrect trigger settings Trigger Delay too short 26 4 4 Incorrect trigger settings Trigger Delay too long 27 4 5 Trigger Delay too short Left acoustic wave position in the crystal when the optical pulse is in the crystal Right Equivalent spectrum and time graphs 27 4 6 Trigger Delay too long Left acoustic wave position in the crystal when the optic...

Страница 7: ...nitor maintenance panel 47 5 13 Selection of Parameters Directory 52 5 14 Default parameter set selection 53 5 15 poll message no alarm 54 5 16 poll message alarm s present 54 5 17 L2 indicator blinking alarm s present 54 5 18 poll message no alarm 55 5 19 Exhaust fan alarm present 56 5 20 Monitor Configuration panel several alarms 57 5 21 poll message several alarms present 57 5 22 missed trigger...

Страница 8: ...MA RF cable USB link synchro signal TTL 50 Ohm from Laser system SMA SMA RF cable 50 Ω 10 350 MHz 250 Vpkpk an acousto optic crystal an RF generator a Laptop computer 1 1 1 Crystal unit The crystal is an active component which through the acousto optic interaction allows to shape the spectral phase and amplitude of an optical pulse The theory and performance of this interaction are described in ch...

Страница 9: ... of the optical and acoustic waveforms triggering process and other functions that cannot be handled by the computer The generator produces a sampled arbitrary waveform signal The signal repeats periodically when the unit is programmed in the continuous mode and is generated only once for each trigger signal in the single mode On the front panel trigger and aux are inputs controlling the generatio...

Страница 10: ...of ϕ ω as a polynomial 7 reading A ω and ϕ ω from files 8 setting of the waveform amplitude and duration 9 storing and retrieving of waveforms for waveform combination multiple pulses 10 sending launching waveform to the RF unit 11 choice of two waveforms or to alternate at each trigger between two stored waveforms Figure 1 2 DazzlerTM software front panel All the above programmation is done from ...

Страница 11: ...1 1 3 enabling disabling remote control mode 4 various monitoring functions Details are found in chapter 5 The GUI main panel is shown with superimposed dark green arrows to the controls mentioned below V3 00 8th April 2019 ContentsTable FiguresTable 5 94 ...

Страница 12: ... collinearity in terms of Poynting vectors Section 2 1 3 gives more details on the pulse shaping mechanism 2 1 1 Phase matching conditions As for all three wave mixing processes the phase matching condition for monochromatic plane waves is defined by two conditions wave vector conservation momentum conservation frequency conservation quantum energy conservation Mathematically these conditions can ...

Страница 13: ...ship can be viewed as an implicit equation which links acoustic and optical frequencies In thick crystals this link is an almost one to one relationship i e bijective between acoustic and optical frequencies In other words a single acoustic frequency diffracts a single optical frequency 2 1 2 Poynting vectors In most acousto optic modulators a transverse acoustic wave interacts with the input opti...

Страница 14: ...tions but less self explanatory Explanation in terms of group delay A schematic of the AOPDF is shown in Figure 3 4 An acoustic wave is launched by a trans ducer excited by a time dependent radio frequency RF electronic signal The acoustic wave propagates with a velocity V along the z axis and hence reproduces spatially the temporal shape of the RF signal Figure 2 2 Explanation of the Dazzler prin...

Страница 15: ...S αω Ein ω S ωac 2 6 The spectral phase of the diffracted optical pulse ϕdiff ω can be written ϕdiff ω ϕac ωac ϕin ω 2 7 where ϕac and ϕin are respectively the spectral phase of the acoustic and optical input waves This relationship shows that the spectral shaping is performed via a phase transfer from the acoustic wave to the optical input one Let s consider H ω the AOPDF optical transfer functio...

Страница 16: ...the actual acoustical power density k kdiff e kin o kac uac is the phase matching mismatch along the acoustic prop agation direction L is the crystal length along the acoustic propagation direction P0 is a characteristic acoustic power given for the DazzlerTM HR models P0 3 7 106 λ L 2 in W mm2 2 14 For L 25 mm λ 800 nm P0 3 8 mW mm2 For L 45 mm λ 1 µm P0 1 8 mW mm2 When P P0 and k 0 the transfer ...

Страница 17: ...dth of input optical signal in wavelengths the number of independent programming points of the AOPDF is N λ δλ1 2 1 25 δn L λ λ2 L 8 9 λ λ2 2 17 For L 25 mm λ 100 nm 800 nm N 439 For L 25 mm λ 300 nm 800 nm N 1318 For L 45 mm λ 20 nm 1 µm N 101 2 2 4 Input beam angular aperture divergence With a WB crystal cut the divergence of the input beam must be inferior to δθ1 2 n0 δθ0 1 2 2 47 δλ λ 1 2 22 λ...

Страница 18: ... Equation 2 4 the maximal pulse shaping capability τmax can be expressed by τmax nge ω ngo ω ωL c 2 22 This relation can be written to first order in n no2 τmax ng ω cos2 θoωL c 2 23 where ng 3 is the group birefringence of the crystal For HR25 DazzlerTM systems the maximal pulse shaping capability is 8 5 ps at 800 nm 2 2 8 Crystal dispersion compensation The DazzlerTM crystal introduces an optica...

Страница 19: ... input and output faces are not interchangeable The table below gives the angles of the diffracted and transmitted beams with regards to the input direction for the HR and WB Dazzler models WB model HRmodel Diffracted beam angle 1 0 1 4 Transmitted beam angle 3 6 4 5 Another point to note is that there is inherently a displacement no angular change of the diffracted beam depending on the point of ...

Страница 20: ...ω 0 χ 0 χ 3 0 g ω 1 k exp ω ω 1 δω 1 2 ω 1 2πC λ 1 λ 1 hole position χ 1 δλ 1 2λ 1 δλ 1 hole width δω 1 ω 1 χ 1 χ 3 1 2 k hole depth Selector Control Setting dials A ω A dial ω polynomial φ ω φ dial ω file A ω A f ile ω file φ ω φ f ile ω both A ω A dial ω A f ile ω both φ ω φ dial ω φ f ile ω Spectrum combinations S ω A ω exp i φ ω a exp i φ S saved ω In the table above S ω corresponds to the AOP...

Страница 21: ...is trigger signal occurs Trigger to Laser microseconds before the optic pulse going through the crystal This time interval is approximately equal to the acoustic propagation time into the crystal1 The triggering configuration varies with the experimental setup 10Hz kHz lasers 100kHz For operational details see chapter 4 3 1 1 Connecting the unit and starting the software 1 connect the RF output to...

Страница 22: ...k that the single mode is activated on the software front panel continuous switch down to set it down click below the switch center see subsection 5 1 7 12 select the correct trigger settings trig and mode panel of the Dazzler software chapter chapter 4 For cabling tips to limit the noise which may impair the proper operation of the system refer to chapter 7 3 1 2 Define the general settings Blue ...

Страница 23: ...e menu file exit item or by checking the red cross box at the top right corner of the window The user is asked to confirm the action and whether the current status of the panels should be saved to be restored on the next program start up One should note that the RF generator is NOT STOPPED by exiting the program to stop generating the acoustic signal select the zero slider Figure 5 2 and click on ...

Страница 24: ...ter the compressor More complex pulse shaping can also be achieved such as multiple pulses or optimized pulse shape for a specific experiment 3 2 2 Dazzler after an optical parametric amplifier The Dazzler can be used as a pulse shaper at the output of an OPA An example of setup is shown on the Figure 3 2 The Dazzler enables to control the output pulse shape for example the generation of two or mo...

Страница 25: ...rection is perpendicular to the plane of diffraction Note that while the input beam is polarized perpendicularly to the diffraction plane the diffracted beam is polarized parallel to the diffraction plane Make sure that the output polarization fits your laser setup For proper operation the input optical beam has to be aligned with the acoustic axis Fig ure 3 4 For a precise alignment the crystal s...

Страница 26: ...input face Figure 3 6 Example of spectrum with hole Feed the diffracted beam into a well calibrated spectrometer Verify the wavelength at which the hole feature appears If a difference dλ occurs with the programmed value and this difference is significant i e larger than 10nm there is a setup problem a non exhaustive list of possible causes is the input light polarisation orientation is incorrect ...

Страница 27: ...sions 5 8mm2 Set the x and y positions so that the laser beam is approximately in the center of the diffraction region 3 change the waveform of the Dazzler to produce a short acoustic signal by reducing the second order phase coefficient see Figure 3 7 A typical signal on the oscilloscope is shown for this example The duration of this signal is the propagation time through the crystal txtal typica...

Страница 28: ...e 2 increase the second order phase coefficient order 2 on the GUI to produce a quasi flat signal covering the full time window Figure 3 8 Do not pay attention to the red curve on the spectrum graph The signal is willfully truncated in the crystal to adjust the superposition of the optical incident pulse with the acoustic wave Please keep in mind that for other Dazzler operations the red and black...

Страница 29: ...DAZZLERTM system manual Part I installation operation 3 3 Figure 3 8 Chirped Pulse used to adjust the x and y position V3 00 8th April 2019 ContentsTable FiguresTable 23 94 ...

Страница 30: ...n V5201 The following description is valid for software versions V520b and above 4 1 1 Wiring and signal level The external synchronization signal connected to the trigger BNC input of the RF generator must be properly terminated2 the pulse signal should come from a 50Ω source via 50Ω cables and be terminated properly with a 50Ω load Make sure to follow the prescriptions given in Figure 7 2 4 1 2 ...

Страница 31: ...ble when starting the RF cycle by the delayed previ ous trigger pulse4 This mode of operation is called Trig on Previous mode see subsec tion 4 3 2 Figure 4 1 Optimum trigger settings Figure 4 1 shows when these conditions are fulfilled resulting in a positive Trigger Delay With these settings the acoustic wave is fully contained in the crystal when the optical wave goes through To illustrate the ...

Страница 32: ...ings Trigger Delay too short When Trigger Delay is set too long the acoustic wave is not yet entirely in the crystal when the light pulse arrives The trailing part of the wave is missing 4 2 The Trig Mode panel The DazzlerTM software provides a user friendly interface to enter the delays Tp TXtal Trigger to Laser Trigger Delay correctly based on experiment parameters Before opening the Trig Mode p...

Страница 33: ...l when the optical pulse is in the crystal Right Equivalent spectrum and time graphs Figure 4 7 Trig Mode panel activation When the Trig Mode panel is opened for the first time the warning message shown on Fig ure 4 8 is displayed It gives the precision of the trigger delay generation subsection 4 3 3 To reach this precision level all waveforms have to be re loaded after any change in the Trigger ...

Страница 34: ... the window 4 2 1 Panel presentation D C B A Figure 4 9 Trig Mode panel WR25 DazzlerTM typical values The Trig Mode panel features the following parts from top to bottom on Figure 4 9 A a message banner situated on the top left corner shows the same polling message as the one in the DazzlerTM main window B Parameters that are used to compute delays 6 when open every second the trigger frequency is...

Страница 35: ...nal Source variable duty cycle and also when Trigger Mode selects External Source and the parameters require Trig on Previous mode The user has to enter the exact value corresponding to the laser trigger source see Figure 4 15 for details a Control b Indicator When an indicator the box shows the actual Repetition Frequency as counted by the RF generator 4 10 b Figure 4 10 Different Repetition Freq...

Страница 36: ...orking in Trig on Previous mode adjust Repetition Frequency to the value corre sponding to the setup 3 Send the diffracted beam to a spectrometer REMINDER amplifiers should not be used until the Trigger to Laser value is correctly adjusted 4 Set the phase option to polynomial and the order 3 and order 4 to zero Use the delay dial to center the signal on the time graph 5 Increase the second order p...

Страница 37: ...d when condition Equation 4 1 is verified Trigger to Laser Trigger Delay TXtal Tp 4 1 Or in simpler words the laser system provides a trigger signal sufficently ahead of the optic pulse to allow synchronization with adjustment of a short delay few µs Signals in this mode are represented on figure Figure 4 13 Trigger Propagation Tp Laser Trigger Delay Trigger to Laser Acoustic signal at input face ...

Страница 38: ...eriod 1 Repetition Frequency is added to the right hand side of Equation 4 1 Trigger Delay Trigger to Laser TXtal Tp 1 RepRate 4 2 Since the laser repetition rate is used by the Trigger Delay computation its value must be set manually by the user This avoids the delay value to fluctuate with Repetition Frequency measurements see subsection 4 2 2 for details 4 3 3 Influence of Trigger Delay limits ...

Страница 39: ...ator the DazzlerTM software adds or subtracts a delay to the spectral phase of the generated waveform For standard HR25 models with V5 boards the precision is typically 0 18 µs Because the software uses the spectral phase of the generated waveform to reach this precision level all waveforms to be used have to be re loaded after a change of the Trigger to Laser value8 4 3 4 No Delay If one needs to...

Страница 40: ...tition rates at the expense of a lower pulse shaping capability and some small phase variations between consecutive pulses This mode is called High Repetition Rate and is switched on automatically when 1 RepRate Trigger to Laser Tp TXtal dMin 4 4 When High Repetition Rate mode is active a blinking indicator appears in the upper right corner of the Trig Mode panel The number of optical pulses diffr...

Страница 41: ...ystal τAc µs after without interfering with the next cycle This leads to loss in pulse shaping as the acoustic pulse maximum length τmax Equation 4 6 is shorter than TXtal N τmax 1 Repetition Frequency TXtal N Repetition Frequency N 1 Repetition Frequency TXtal 4 6 The pulse shaping capability loss is shown by yellow bars on the time graph of the DazzlerTM front panel figure Figure 4 20 see below ...

Страница 42: ...chapter 5 Software Operation 5 1 Front panel When starting the DazzlerTM software the following window appears Figure 5 1 DazzlerTM GUI software front panel 36 ...

Страница 43: ...nt Gain the diffraction efficiency changes with the phase control because of peak values and normalization And with Constant Gain the diffraction efficiency remains the same independently of phase control except if the signal amplitude is so large that saturation would occur in which case loading is prevented When using constant gain check that the signal amplitude does not exceed the saturation l...

Страница 44: ...amplitude which is the product of the dials result and the file result 5 1 3 Green Area spectral phase control The spectral phase selector is similar to the am plitude selector control When polynomial is se lected the dials program a polynomial phase func tion with respect to the specified central wave length This central wavelength is automatically following the center position of the amplitude s...

Страница 45: ...utton The values of the Amp for Amplitude and Phase controls correspond respectively to a and φ in the above formula see section 2 3 For example in order to generate two identical pulses separated by a given delay proceed as follows 1 set the parameters for a single pulse 2 press the save button with the memory buffer value set at 0 3 shift in time by changing the delay in the green area 4 set the...

Страница 46: ...te delimited by the purple rectangle and if the distortion due to amplitude or phase corrections is not leading to high peak power implying loss of spectral resolution non linearities REMARK Artefacts of Moire type could appear on the signal because of the resolution of the screen therefore do not always trust small fluctuations or details 5 1 6 Loaded waves This small display shows the RF waves c...

Страница 47: ... is initiated and if successful the online indicator lights showing that the software operates in online mode When in online mode the generator is periodically interrogated and the result of this polling process is displayed in the poll message text line see Figure 5 15 This activity is shown in the message with the cycling every second of the last two characters between the following The informat...

Страница 48: ... and blocked before the generator condition is actually changed the top right message banner Figure 5 6 shows actual values the trigger frequency alarms and warnings The power damage ratio value reflects the current RF power com pared to the maximum allowed power for the currently active waveform The parameter f limit reflects the ratio of the measured repetition frequency over the maximum possi b...

Страница 49: ...hanging mode Each wave sent to the generator contains meta data that gives information on the power damage threshold and the minimum time period in which one cannot send another RF waveform to the crystal without reaching this threshold Any trigger occurring during this time period is ignored and a missed trigger warning appears Figure 5 10 It is possible to visualize the signal corresponding to t...

Страница 50: ...ems To ease operation the items save default restore default The save default menu is equivalent as saving settings on exit it will save the current waveform and the trigger settings restore default will only restore the current waveform Trigger settings cannot be restored in this way The information is kept in the parameters directory section 5 5 The menu item exit stops the program 5 2 2 Setup m...

Страница 51: ...nd their descriptions Alarms zone the path to the parameters folder Parameters Path zone the path to the default directory folder Data Path zone see subsection 5 3 1 the RF generator configuration Sampling Frequency Nb of Samples DAC Latch etc When asking for support to after sales service a screenshot copy of this window will be appre ciated as it directly contains these important points the Dazz...

Страница 52: ... Monitor configuration panel to force serialization of actions by stopping the poll debugging to access low level commands of the on board microcontroller This panel must not be used without instructions from Fastlite V3 00 8th April 2019 ContentsTable FiguresTable 46 94 ...

Страница 53: ...ogram Files Dazzler without escalating to admin privileges The subtree C dazzler is given rw access to everyone during the installation thus solving the permissions problems The default directory is by default c dazzler data for a single generator and c data 1 and c dazzler data 2 for installations with 2 Dazzlers In single Dazzler installations the default directory is defined in the INI file whi...

Страница 54: ...rs when starting the Dazzler program 5 3 3 C dazzler This folder C dazzler has been required since the remote access was introduced 2003 This folder holds information which must be available from anywhere Present content folder data is the default directory for single Dazzler installations paths txt written by the Dazzler program on remote enable changes see subsec tion 6 2 4 5 4 Wave files These ...

Страница 55: ...tion 5 4 1 for format 5 4 1 amp txt and phase txt file format Both arrays describing spectral amplitude and phase should be written in the files as two column arrays with the tabulation character as separator Excel and LabVIEW spreadsheet standard txt format First column wavelength in nm in increasing order Second column amplitude or phase value for that wavelength Units for the phase are radians ...

Страница 56: ...ent partition than the system The location of that directory is defined in the file C dazzler data params txt One should find here a line of the form D param folder nickname Parameters Directory Path The location of the parameter folder can be changed see subsection 5 5 2 for details The parameter files stored in this directory are ro DazMain txt contains factory parameters rw DazCurrent txt setti...

Страница 57: ...the waveform was programmed using7 the files AMP txt or PHASE TXT the contents of these two files are stored in wave txt in sections AMP and or PHASE When the waveform parameters are restored the contents of the files AMP TXT or PHASE TXT are overwritten back to what they were when the waveform was saved The same principle applies for the waveforms using combinations between multiple buffers Each ...

Страница 58: ...nd you a copy of the parameters folder as when delivered All the adjustments made during the installation setup need to be re done Good practise is to include the parameter folder in the regular backup scheme 5 5 2 Location of parameters files One may have to define explicitly the location of the parameter folder to the software especially after a reinstallation on another computer On a working in...

Страница 59: ...ditions which may raise alarms are checked regularly polling rate above 10Hz the presence of an alarm is indicated by the poll message see software front panel which becomes red and bold as shown below and the L2 indicator blinks red alarm conditions are sticky this means the alarm needs to occur only once to be remem bered until it is cleared by an explicit operator acknowledgement Thus a tempora...

Страница 60: ...m text attempts to identify the faulty fan the RF amplifier temperature is too high11 Exhaust fan speed The exhaust fan is very important for cooling the generator It is located on the generator rear panel Its nominal speed is 3900rpm The speed is based on the measure of the fan rotation sensor period An alarm is raised when the speed is below 50 of the nominal speed which is shown right between i...

Страница 61: ... 5 18 poll message no alarm Note that the monitor configuration shows the current fan speed hence a speed alarm could have been raised when the speed was abnormal but is now back to normal as shown on Figure 5 19 V3 00 8th April 2019 ContentsTable FiguresTable 55 94 ...

Страница 62: ...nel Its nominal speed is 5900rpm An alarm is raised when the speed is below 50 of nominal In this case the message FAN Exhaust or Aux fan speed too low appears in the alarm box of the monitor configuration panel as for the exhaust fan alarm On the software front panel the poll message indicates that the fan alarm has been raised Curative actions Immediate switch off the generator as soon as feasib...

Страница 63: ... Long term investigate cooling conditions and liaise with Fastlite Things to investigate 1 obstructions in front of the air inlet outlet openings 2 generator positionned on a hot surface 3 not enough breathing space at the rear exhaust fan When two alarms are raised a message specific to each alarm appears in the alarm box of the Monitor Configuration panel On the software front panel the poll mes...

Страница 64: ...hreshold The Dazzler program prevents such a situation to happen by pre venting loading or switching waveforms as appropriate This may happen after a waveform is loaded and the trigger frequency is increased In order to protect the crystal triggers are ignored during a protection period computed to limit the average power 5 7 3 Missed triggers unreported The Dazzler RF Generator is used to generat...

Страница 65: ... display memory buffer and 33 37 5ns 1 24µs to transfer a packet 1 header byte 32 byte data from ram to display buffer a single waveform transfer lasts NPAK 1 24 228µs This gives a global value the actual hardware and firmware may differ When the display mode is Alternate two waveforms are required 5 8 Troubleshooting 5 8 1 Missing parameters Some parameters are absolutely required by the software...

Страница 66: ...ters directory see subsubsection 5 5 1 along with as much screenshots as possible At the minimum copies of the main window and of the Monitor Configuration will be greatly appreciated Parameters set should put in a ZIP archive while the screen dumps should be stored as PNG as this format uses 20 times less space than the default Windows BMP12 Checklist for submitting problems the serial number of ...

Страница 67: ...ed text file mode In this text file mode the Dazzler program acts like a spooler operating on text files this is slow but very general The text file mode interface is based on text files generated by the remote user program This mechanism has some advantages the remote user program can be written in any programming environment or lan guage e g LabView Visual Basic C Python etc the remote requester...

Страница 68: ...l be operated manually The remote enabled indicator lights up on the front panel When the main Dazzler program is running in this mode it periodically checks for the existence of a text file named request txt in the default directory see subsection 5 3 1 The active indicator blinks for a short time whenever such a file is found In the simpler case the file contains a single line of text describing...

Страница 69: ...e wave file The remaining lines hold the commands Processing order is command dependent The LOAD button is only pressed at the end of processing the wavefile keys and commands are case insensitive Figure 6 1 Remote text using two files Processing of the request file information is as follows 1 star commands first 2 wave file controls including amp phase section 3 waveform loading If preferred it i...

Страница 70: ... request txt file The adequate wave text file can either be generated from the Dazzler program using the save as menu option or directly written by the user remote control program 6 2 4 File C dazzler paths txt The file c data paths txt is a leftover relict from early use of the Dazzler in network configurations This file is now only an indicator for two paths used by the last Dazzler GUI having c...

Страница 71: ...erator limit or if the memory n is not present Dazzler generators have various amount of memory this is indicated by the Nb of Mems RAM box on monitor configuration panel HW Figure 6 2 Out of range memory pointer MEMB n Changes the memory slot pointed by B HW ONLINE b Operates the on off line status HW ONLYCOMPUTE b Does not load waveform just computes it and write results into c dazzler data Spec...

Страница 72: ...equal to wave after the star commands from the wave information When such wave keyword is found all the remaining of the request file is considered to be the content of the wave file potentially including amp and phase subsections see section 5 4 The use of the wave keyword is mutually exclusive with the specification of a wave file path as first line of the request If both are included behavior i...

Страница 73: ...ram must follows the following steps 1 Initialization which opens a communication channel with the DazzlerTM and prepares for execution the different functions that will be remotely called 2 Use the different functions provided to perform the necessary actions on the DazzlerTM The description of these functions is delivered as a CHM LabVIEW typical help file included with the library The functions...

Страница 74: ...ault directory see subsection 5 3 1 The connection is kept open by the library until the call of close vi see below The input parameter VIs to initialize is supposed to provide the list of the remote functions that will be called by the remote program This is mainly for performance purposes If not connected the library will prepare itself for the execution of every remote function provided in the ...

Страница 75: ...e client program stops This closes the network connection with the Dazzler software Failure to close properly will consume resources slow down and eventually crash the programs involved including the Dazzler12 12 Not releasing resources often causes memory leaks V3 00 8th April 2019 ContentsTable FiguresTable 69 94 ...

Страница 76: ...cted 7 1 1 Ground plane layout crossings The top of the optical table the mechanical reference should be connected to earth for safety For EMI EMC control this is not effective and the following tips may have to be implemented The first step is to turn the mechanical reference into a good RF ground plane RF electrical reference If the sheet is made of aluminum alloy the surface may be not conducti...

Страница 77: ...m 50Ω sources via 50Ω cables and be terminated properly with a 50Ω load It is often necessary to insert a Tee to observe a signal To minimize the impedance mis match the impedance of the input fed by the Tee should be high while the signal is terminated at the end Thus the impedance of the Dazzler inputs trigger and aux is kept high so as to feed an oscilloscope input which has an internal 50Ω ter...

Страница 78: ... other sink 50Ω 50Ω signal trigger source 50Ω scope HighZ RF generator S2 S1 trig aux signal trigger source 50Ω load 50Ω load RF generator S2 S1 trig aux signal trigger source 50Ω RF generator S2 S1 trig aux Figure 7 2 Correct TRIGGER wirings V3 00 8th April 2019 ContentsTable FiguresTable 72 94 ...

Страница 79: ...DAZZLERTM system manual Part I installation operation 7 3 7 3 Practical examples V3 00 8th April 2019 ContentsTable FiguresTable 73 94 ...

Страница 80: ...DAZZLERTM system manual Part I installation operation 7 3 V3 00 8th April 2019 ContentsTable FiguresTable 74 94 ...

Страница 81: ...DAZZLERTM system manual Part I installation operation 7 3 V3 00 8th April 2019 ContentsTable FiguresTable 75 94 ...

Страница 82: ...DAZZLERTM system manual Part I installation operation 7 3 V3 00 8th April 2019 ContentsTable FiguresTable 76 94 ...

Страница 83: ...DAZZLERTM system manual Part I installation operation 7 3 V3 00 8th April 2019 ContentsTable FiguresTable 77 94 ...

Страница 84: ...de see section 8 6 for timing diagrams On the front panel are found the inputs trigger and aux controlling the generation process BNC outputs S1 S2 S3 and S4 on the rear panel are used for driving data acquisition control equipment and for monitoring signals with an oscilloscope for troubleshooting Figure 1 1 shows a simplified schematic of the RF generator 8 2 Indicators This sub section describe...

Страница 85: ... the displayed waveform as required by some RF amplifiers 8 2 3 L2 indicator The red L2 indicator signals alarm conditions it blinks rapidly when an alarm condition has been detected see section 5 19 The normal condition is off or unlit 8 2 4 Trigger indicator This is the LED just above the trigger in BNC input socket This indicator will lit when the trigger rate is measured after the generator go...

Страница 86: ...s Dazzler input chapter 7 is full of practical advice to avoid unstabilities due to EMI 8 4 Input signals 8 4 1 Input signal trigger This signal is essential to the successful operation of the Dazzler with the laser system Please refer to chapter 4 for more details The following actions are started by the trigger the rising edge of the trigger pulse starts a retriggerable multivibratortrigina sub ...

Страница 87: ...ad or to the crystal failure to provide a load may damage the RF generator The nominal output is 10 W translating to 60 V peak to peak This signal should not be connected directly to an oscilloscope but via a 40 dB power attenuator otherwise the oscillo scope is likely to be permanently damaged This point is very important as many calibration procedures imply to connect an oscilloscope on this sig...

Страница 88: ...he RF signal yellow trace is slightly late with respect to gate The delay between the rising edge of trigger and the start of RF generation depends of the sampling frequency Fdata and varies from 300ns to 2 3µs This delay is called gendel Figure 8 3 has similar conditions as in Figure 8 1 except that the trigger mode has been changed to no delay mode notice the small delay between trigger and trig...

Страница 89: ...DAZZLERTM system manual Part I installation operation 8 6 Figure 8 1 RF cycle programmable delay Figure 8 2 RF cycle no delay V3 00 8th April 2019 ContentsTable FiguresTable 83 94 ...

Страница 90: ...ry B has 3 peaks The next oscillogram on Figure 8 6 shows when both continuous mode alternate are selected The red trace shows gate while hiwhenA is shown on the green trace This demonstrates the alternation of A B and that the signal hiwhenA can be used to synchronize external equipment9 hiwhenA changes state on the trailing edge at the end of gate This gives enough time to the synchronised equip...

Страница 91: ...DAZZLERTM system manual Part I installation operation 8 6 Figure 8 4 Continuous mode Figure 8 5 Alternate mode V3 00 8th April 2019 ContentsTable FiguresTable 85 94 ...

Страница 92: ...ux is sampled at the trailing edge of gate A memory transfer from SRAM to FIFO is initiated whenever a change in aux is detected Using memory SRAM TransferTime T xtalxFdata x 3 80E6 x 33 32 if TriggerPeriod TransferTime there will missed triggers It is also used to synchronize the sequences in burst mode 8 7 Output signals S1 S4 These signals are defined by the hardware options purchased as well a...

Страница 93: ...ion T1out is forced in internal triggering mode total of 8 choices see the implemented signals by opening the Trig Mode panel 8 7 3 Output signal list extracted from Siegman PROD DAZZLER GZ0655 txt signal usage RF board V5 x CHOP and FIFOGATE triggers N in streaming sequence GATE and CHOP pulsed triggers N 1 N GATE and CHOP pulsed triggers 1 N CHOP inverted triggers N GATE OFF during RF signal GAT...

Страница 94: ...TRIGINA trigger block VCC HI level 8 7 4 Descriptions of selectable signals hiwhenA high when wave A is played is useful in alternate mode or when waveform B is selected and a high level is applied to the AUX terminal Logic level LO corresponds to waveform B logic HI corresponds to waveform A The tparity choice is based on the triggers processed and not on the waveform selection traces red hiwhenA...

Страница 95: ...f the aux signal used to verify operation of aux trigina trigger blocking All external triggers received during trigina are inhibited Note that each trigger occuring within trigina restart the monostable for a period and thus lengthen the signal This is wanted to filter out rebounds but will fail to recognize any trigger if the frequency is above 1 trigina It is possible to adjust this blocking ti...

Страница 96: ...e Dazzler program they may be pulsing They are steady if the DazzlerTM program is only polling fsmpcnt 4 fsmpcnt 5 are the sampling frequency divided by 32 and 64 used to verify the operation or cabling When in low jitter operation can be used to connect a frequency meter and verify that the reference clock is correct Qclock is the internal quartz clock divided by 4 20 MHz Used to verify operation...

Страница 97: ...DAZZLERTM system manual Part I installation operation 8 8 V3 00 8th April 2019 ContentsTable FiguresTable 91 94 ...

Страница 98: ...cribes the standard Dazzler TM model availables To download the specifications corresponding to one model please go to our website http www fastlite com Custom systems are available upon request Please contact Fastlite at info fastlite com V3 00 8th April 2019 ContentsTable FiguresTable 92 94 ...

Страница 99: ... Ch Spielmann F Krausz Sub 10 fs terawatt scale Ti sapphire laser system Optics Letters Vol 28 p 1832 1834 2003 6 D Kaplan P Tournois B Chatel A Monmayrant Tunable wavelength pulse shaping of visible NOPA outputs with an Acousto Optic Programmable Dispersive Filter 14th International Conference on Ultrafast Phenomena paper TuE40 2004 7 A Monmayrant A Arbouet B Girard B Chatel A Barman B J Whitaker...

Страница 100: ...DAZZLERTM system manual Part I installation operation 8 8 Lasers and Electro Optics 2003 CLEO 03 Conference on Baltimore MD USA pp 1176 1177 2003 V3 00 8th April 2019 ContentsTable FiguresTable 94 94 ...

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