OPTOGAMA LPA-A v2 Series, Руководство пользователя

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2. Operation principle
LPA-A consists of zero-order half-waveplate and High
contrast Brewster type thin film polariser.
Zero-order half-waveplate rotates the polarisation. Brewster
type thin polariser passes P-polarised and reflects the S-
polarised laser beam. Waveplate and polariser are coated
for the desired wavelength. The attenuation adjustment is
achieved by motorised rotating of the waveplate, which is
located in the incident of the laser beam. The attenuation
level is controlled by the software in 0.1-98% range
.
NOTE: Before use calibration is required
CAUTION! Before increasing laser power make sure the
device is aligned and there is no beam cut. It may damage
optical elements.
2.1.Contrast improvement. Angle
adjustment
Incident light’s angle α should be adjusted to improve device
contrast (± 2 deg maximum). Use HEX 1,5 key.
• Clock-wise to decrease angle
• Counter clock-wise to increase angle
Fig 2. Schematic explanation of optical design of laser power attenuator
(LPA-A)
2.2. Features and advantages
• Integrated controller
• Absolute position encoder - no homing required
• High accuracy - ±0.005 deg
(less than ±0.01% of laser power)
• Resolution - 0.002 deg, 7.2 arcsec, 0.035 mrad
• Robust design
• Clear aperture - ø15 mm
• Fast adjustment - less than 0.2 sec (min to max)
• High damage threshold:
up to 10J/cm
2
(10 ns @ 1064 nm)
• Adjustable polariser angle
2.3.Optical design
LPA-A optical elements are coated for high LIDT (10 (J/cm
2
)
(10 ns @ 1064 nm) and can be applied for high power
lasers. There are Reflection and Transmission configurations:
Fig 1. Schematic explanations of optical design of transmission (LPA-A)
type laser power attenuator.
Transmission
S - polarised
P - polarised
Half waveplate
Brewster type
polariser
Input
Output
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