Performance test of a photoaddressed liquid crystal spatial light modulator with gallium nitride as both a photoconductive layer and a conductive layer

1. Materials and devicesMaterial: Silicon doped and magnesium doped gallium nitride film (thickness 5μm) provided by Suzhou Nawei Company is plated on sapphire glass substrate.Device: Gallium nitride acts as both conductive layer and photoconductive layer, combined with polyimide (PI) oriented film, spacer and HFS962000-100+0.15%S811 type liquid crystal.2. Test the instrumentThe spectrometer (Cary 5000) is used to measure the gallium nitride absorption spectrum (wavelength range 200-1100 nm).Uv LED light source (peak wavelength 370 nm, half-height full width 11 nm) as the write light.1053 nm laser source with polarizer (P1, P2), 4f optical system, CMOS camera (light intensity detection).The response time was measured by oscilloscope (RIGOL DS1202) and photocell (PDA36A2).3. Test dataThe contrast unit is the value of the normalized light intensity, which is the maximum transmitted light intensity divided by the minimum transmitted light intensity, and the contrast ratio is at least 80:1.The absorption coefficient (cm-1) was calculated by α = Abs·ln(10)/d, and the resolution (lp/mm) was calculated according to the formula (resolution =2^(group number +(element number -1)/6)), and the resolution reached 7.13lp/mm.The unit of response time is s or ms, the response time of the gallium silicon-doped liquid crystal spatial light modulator is 2.474s, and the response time of the magnesium gallium nitride liquid crystal spatial light modulator is 363ms.