THORLABS MC1000 Operating Manual Download

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Doc 1693-D03 Revision B 6/6/00

MC1000

Opto

Opto----Mechanical Chopper

Mechanical Chopper

Operating Manual

THORLABS, Inc.

Ph: (973) 579-7227

435 Route 206N

Fax: (973) 300-3600

Newton, NJ 07860 USA

www.thorlabs.com

PHASE ADJ

EXT EN

REF OUT

EXT REF IN

ENTER

CYCLE

FREQ DOWN

FREQ UP

SETUP

RECALL

FREQUENCY

REF

SELECT

SET

SETUP

SAVE

MODE

PWR

MODEL MC1000 OPTICAL CHOPPER

Summary of Contents for MC1000

Page 1: ...er Mechanical Chopper Mechanical Chopper OperatingManual THORLABS Inc Ph 973 579 7227 435 Route 206N Fax 973 300 3600 Newton NJ 07860 USA www thorlabs com PHASE ADJ EXT EN REF OUT EXT REF IN ENTER CYCLE FREQ DOWN FREQ UP SETUP RECALL FREQUENCY REF SELECT D SET N SET SETUP SAVE MODE PWR MODEL MC1000 OPTICAL CHOPPER ...

Page 2: ...e 10 Setup for External Reference Frequency 10 Selecting the REFERENCE OUT signal 10 Harmonic Reference Generation 10 Setting the Reference Harmonic 10 Setting the Sub Harmonic 11 Combining the Harmonic and Sub Harmonic Modes 11 2 Frequency Chopping 11 Setting the Chopping Speed in the 2 Frequency Mode 11 Setting the Chopper Blade 11 Adjusting the Chopper Phase 12 Phase Adjustment Related Stabilit...

Page 3: ...lay will go through a startup sequence first all of the display segments and LEDs are lit then the firmware rev level is displayed then the current blade setting is displayed The display should show b 10 for the 10 slot blade If not press the FREQ UP button until the b 10 message is displayed and then release the button The unit will time out after a second or two and go into a standby mode with t...

Page 4: ...0 also supports 2 frequency chopping from a single chopper blade A special blade is available with 7 outer slots and 5 inner slots This slot combination allows a single beam to be split and individually modulated for ratiometric experiments Other applications include pump probe experiments where the pump beam is modulated at the outer frequency while modulating a probe beam at the inner frequency ...

Page 5: ...ousing and the photo interrupter motion detection electronics The key features of the chopper head are highlighted in Figure 1 Figure 1 Optical Head Features Feature Description 1 Precision Chopper Blade available in 10 15 30 slots and a 7 5 2 frequency 2 1 16 Hex Mounting Screws and lock washers qty 3 3 Photo interrupter Speed Sensor 4 Blade Hub 5 Modular Interface Connector 6 Mounting Base ...

Page 6: ...ECALL and SAVE The currently active mode is indicated by the LED above the legend Note the available input modes are dependent on the operating state i e the SET N and SET D are not active when operating in the internal reference mode 6 SAVE SETUP When this LED is lit the user can save the current configuration to one of five setups Use the FREQ UP CYCLE key to select the setup number and press th...

Page 7: ...e The harmonic multiplier can be used with the sub harmonic divider D to create fractional harmonics i e chopper frequency fchopper REFEXT N D 10 REF SELECT This key allows the REF OUT signal to be selected from a number of sources depending on the operating mode selected Operating Mode Available sync sources Internal Reference Mode OUT SYN External Reference OUT 2 Frequency Blade OUT SYN SUM DIFF...

Page 8: ...Panel Feature Description 1 RS 232 Serial Port Connector 2 Modular interface connector for the optical head 3 Cooling fan 4 AC input and fuse receptacle OPTICAL HEAD RS 232 Manufactured by 230VAC 50 60Hz 115VAC 50 60Hz POWER 10W MAX 125mA Type T FUSE 250mA Type T FUSE Newton NJ USA ...

Page 9: ...e for a lock in amplifier the chopper wheel frequency will be used since it provides a direct measurement of the chopper phase and frequency The chopper wheel reference is derived from a photo interrupter on the optical head that senses the motion of the chopper blade The internal frequency synthesizer has slightly less phase jitter than the chopper wheel reference since it is not effected by exte...

Page 10: ...speed will equal the external reference frequency the harmonic multiplier N and the sub harmonic divider D must each be set to 1 The check these values use the MODE key to select the N and D parameters and adjust their values as necessary 5 The chopper should adjust its speed and lock onto the reference within a few seconds as indicated by the chopper speed shown on the digital display Selecting t...

Page 11: ...is unique prime number combination allows the same chopper to discriminately chop two different light paths This can be used in ratiometric measurements and pump probe type experiments The MC1000 provides two additional reference outputs in this mode The SUM and the DIFFERENCE reference frequencies track the combined signal paths when they are frequency mixed together The example below illustrates...

Page 12: ...phase of the chopper wheel is continuously adjustable from π to π 180 to 180 The phase adjustment applies to all operating modes and is independent of the chopping frequency A 12 turn trim pot is provided on the front panel which is labeled PHASE ADJ Use a small slotted screwdriver to adjust the phase as needed Note When turning the PHASE ADJ pot quickly it is normal to see the chopper phase overs...

Page 13: ...reen to the serial port The current setting is shown in parenthesis after each command The user can select the various commands by typing the letter enclosed in parenthesis at the beginning of each line and the MC1000 will prompt for the user input Typing the RETURN key will exit the input mode without changing the value MC1000 Control Software Revision x xx build xxxx Operating Menu R un motor on...

Page 14: ...the optical head Command I Input Parameters 20 to 1000 10 slot 30 to 1500 15 slot 60 to 3000 30 slot 14 to 700 2 f blade Description This sets the internal reference frequency Note the range is dependent on the blade Command N Input Parameters 1 to 15 Description This sets the harmonic multiplier Command M Input Parameters 1 to 15 Description This sets the sub harmonic divisor Command X Input Para...

Page 15: ...requency Drift 20 ppm C Phase Jitter at 1kHz 0 2 RMS Phase Adjustment 180 to 180 π to π Harmonic Chopping 1 15 th Sub Harmonic Chopping 1 1 to 1 15 th Display 4 Digit LED high intensity Orange 0 56 high digits Reference Input TTL CMOS logic level front panel BNC Reference Output TTL CMOS logic level front panel BNC Operating Voltage 100 120VAC 220 240VAC 50 60Hz switch selectable Operating Tempera...

Page 16: ... with a soft cloth and mild soap detergent or isopropyl alcohol Do not use a solvent based cleaner The optical chopper wheel may build up a layer of dust over time on the leading edges of the wheel To clean the wheel remove it from the optical head and wipe it clean with a cloth dampened in isopropyl alcohol To help prevent the chopper wheel from rusting in high humidity environments wipe the blad...

Page 17: ...e revision level to help us in your assistance www thorlabs com Our website will have up to date application notes and frequently asked questions regarding our products techsupport thorlabs com You can send an detailed email message and one of our application engineers will respond promptly within 1 business day Fax 973 300 3600 Phone 973 579 7227 Mail Thorlabs Inc 435 Route 206N Newton NJ 07860 ...

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