Birefringence mitigation (General)
ShalikaSingh - 00:42, Tuesday 24 January 2023 (3157)
LC calibration
[Shalika, Marc]
 
Objective: Using cross Polarizer method to characterize and calibrate the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
Details: 
 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW, 0.01º, and 88.94º respectively. 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties. See Fig 1 for setup. 
 
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown in Fig 2. The retardance was unwrapped using the method mentioned in 3155. The maximum and minimum retardance obtained using this LC as mentioned by Thorlabs on the datasheet is 916 nm and 19 nm. We obtained the maximum and minimum retardance was 928 nm and 11 nm, during  the calibration performed 
 
4. We compared our calibrated data with data available on the Thorlabs website. Although this data is for another kind of LC(LC1411A) and used for 350-700 nm. The max retardance obtained from this LC was ~450 nm for 405 nm and 635 nm laser. See Fig 2 for reference. For the 1064 nm laser, we have around about double that. We feel at least the calibration is going in a good direction. 
 
Next Step:
 
1. Use Labview for control of temperature and voltage. 
2. Do the calibration at different temperatures. 
 
[Shalika, Marc]
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
Details: 
 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
 
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. The maximum and minimum retardance obtained using this LC as mentioned by Thorlabs on the datasheet is 916nm and 19nm. We obtained the maximum and minimum retardance was 928nm and 11nm, during  the calibration performed 
 
4. We compared our calibrated data with data available on the Thorlabs website. Although this data is for another kind of LC(LC1411A) and used for 350-700nm. The max retardance obtained from this LC was ~450nm for 405nm and 635nm laser. For the 1064nm laser, we have around about double that. We feel at least the calibration is going in a good direction. 
 
Next Step:
 
1. Use Labview for control of temperature and voltage. 
 
 
[Shalika, Marc]
 
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
 
Details: 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. 
 
 
Next Step:
1. Use Labview for control of temperature and voltage. [Shalika, Marc]
 
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
 
Details: 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. 
 
 
Next Step:
1. Use Labview for control of temperature and voltage. [Shalika, Marc]
 
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
 
Details: 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. 
 
 
Next Step:
1. Use Labview for control of temperature and voltage. [Shalika, Marc]
 
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
 
Details: 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. 
 
 
Next Step:
1. Use Labview for control of temperature and voltage. [Shalika, Marc]
 
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
 
Details: 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. 
 
 
Next Step:
1. Use Labview for control of temperature and voltage. 
[Shalika, Marc]
 
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
 
Details: 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. 
 
 
Next Step:
1. Use Labview for control of temperature and voltage. [Shalika, Marc]
 
 
Objective: Using cross Polarizer method to characterize the LC
 
 
Motive: As mentioned in Elog 3155 that we are unable to explore the full range of retardance, so we use the cross-polarizer method to characterize the LC and achieve the full range of retardance as mentioned in the Thorlabs specs. 
 
 
Details: 
1. LP(0º)-  First we used the HWP and QWP which were manually rotated to make a linearly polarized beam. This was ensured by using the polarization camera. The Power, Ellipticity, and Azimuth of the beam were 1.28mW,0.01º, and 88.94º respectively. 
 
 
2. LP(90º)- We placed a PBS after the LP(0º) to distinguish the beam. The  Power, Ellipticity, and Azimuth of the beam were 1.93 µW, 1.13º, and 0.02º respectively. 
 
3. The LC was kept in between the LP(0º) and LP(90º). This introduces the changes in the beam properties.
a. The LC was kept at 25ºC and the fast axis was rotated to obtain the maximum power after LP(90º). The power of the beam was 33µW. 
b. A voltage sweep was done from 0-25V RMS. 
c. The retardance was observed as shown. The retardance was unwrapped using the method mentioned in 3155. 
 
 
Next Step:
1. Use Labview for control of temperature and voltage. 
Images attached to this report
3157_20230130070023_crosspolarizermethod.jpg 3157_20230130070042_elipticitywavesunwrap.png 3157_20230130070054_comparingretardance.png