Optical design for excellent contrast ratio in a reflective horizontal-switching liquid crystal cell

Abstract

In this paper, we propose an optical configuration for a reflective liquid crystal (LC) cell with a single polarizer that can show an excellent contrast ratio by effectively eliminating phase dispersion. The proposed configuration consists of a half-wave retarder, two A-plates, a quarter-wave LC cell and a reflector; the configuration was designed on a Poincaré sphere with the trigonometric method. From the calculation, we confirm that this configuration can show a high contrast ratio as compared with the conventional configuration due to the excellent dark state.

Photon Pair Source based on PPLN‐Waveguides for Entangled Two‐Photon Absorption

“…[13], a more meaningful statement about the presence of eTPA can be given by considering the ratio of biphoton absorption rates 𝛤 . (17) In Equation (17), R represents the transmitted photon count rates through sample (samp) and solvent (solv). The upper indices of R denote the single counts in channels 1 (Singles1) or 2 (Singles2) and the coincidence rates (Coin).…”

“…Figure 9 shows 𝛤 for the investigated quantum dot samples. The data at P SPDC = 0 pW are not shown since no coincidence counts were detected and which cause large uncertainties in the calculation of Equation (17). All values of 𝛤 are close to zero within the error ranges.…”

“…[ 10 ] The spectrum of the generated photon pairs is given by the two‐photon wave function $$$$\begin{align} \mathinner {|{\psi _{\mathrm{SPDC}}}\rangle } &\propto \int f{\left(\omega _{\mathrm{s}},\omega _{\mathrm{i}}\right)}d\omega _{\mathrm{s}}d\omega _{\mathrm{i}} \mathinner {|{1}\rangle }_{\mathrm{s}}\mathinner {|{1}\rangle }_{\mathrm{i}} \end{align}$$$$where $$f({\omega}_{\text{s}},{\omega}_{\text{i}})$$ is called joint spectral amplitude (JSA). [ 17,18 ] $$$$\begin{align} f{\left(\omega _{\mathrm{s}},\omega _{\mathrm{i}}\right)}&=\alpha {\left(\omega _{\mathrm{s}},\omega _{\mathrm{i}}\right)}\varphi {\left(\omega _{\mathrm{s}},\omega _{\mathrm{i}}\right)} \end{align}$$$$It consists of pump envelope α with pump wavelength variance $${\sigma}_{\text{p}}$$ and phase matching function φ with crystal length L . …”