Double-Calibration Method of Imaging Polarimeters

Zijian Han; Deqing Ren

doi:10.3788/AOS202141.2411001

Acta Optica Sinica, Volume. 41, Issue 24, 2411001(2021)

Double-Calibration Method of Imaging Polarimeters

Zijian Han^1,2,3、* and Deqing Ren⁴

¹Nanjing Institute of Astronomical Optics & Technology, National Astronomical Observatories, Chinese Academy of Sciences, Nanjing, Jiangsu 210042, China;

²CAS Key Laboratory of Astronomical Optics & Technology, Nanjing Institute of Astronomical Optics & Technology, Nanjing, Jiangsu 210042, China;

³University of Chinese Academy of Sciences, Beijing 100049, China

⁴Physics & Astronomy Department, California State University Northridge, Northridge, Los Angeles 91330-8268, USA;

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Figures & Tables(8)

Fig. 1. Schematic diagram of the imaging polarimeter

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Fig. 2. Flow chart of the double-calibration process of the imaging polarimeter

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Fig. 3. Experimental setup of the imaging polarimeter

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Fig. 4. Change curve of the evaluation function value during the optimization process

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Fig. 5. Measurement results of the normalized Stokes components. (a) Q/I component; (b) U/I component; (c) V/I component

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Table 1. Type and key parameters of the components in the imaging polarimeter

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Table 1. Type and key parameters of the components in the imaging polarimeter

No.	Component	Manufacturer /Type	Key parameter
1	LAS	Thorlabs HNL050R	5 mW power, random polarization
2	P	Thorlabs LPVIS100	extinction ratio > 100000∶1 at 633 nm
3	QWP	Thorlabs WPQ10ME-633	retardance accuracy <λ/100 at 633 nm
4	LCVR	Thorlabs LCC1223-A	non-compensated, retardance accuracy <λ/50
5	WP	Thorlabs WPQ10	separation angle 1°at 633 nmextinction ratio>10000∶1 at 633 nm
6	step motor rotator(mounting with P/QWP)	Thorlabs K10CR1	absolute accuracy ±0.014°

Table 2. Modulation strategy of the imaging polarimeterunit:(°)
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Table 2. Modulation strategy of the imaging polarimeterunit:(°)
Element Fast axisazimuth LCVR retardance
Step 1 Step 2 Step 3 Step 4
LCVR1 22.5 356.41 298.90 103.00 107.00
LCVR2 45.0 343.70 134.00 49.30 156.00

Table 3. Measurement precisions of the normalized Stokes components before and after the double-calibration
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Table 3. Measurement precisions of the normalized Stokes components before and after the double-calibration
NormalizedStokescomponent RMSE
Before double-calibration After double-calibration
Q/I 2.6970×10^-3 2.1814×10^-3
U/I 7.5149×10^-3 3.8351×10^-3
V/I 6.5679×10^-3 6.2961×10^-3