Low‐Symmetry α‐MoO₃ Heterostructures for Wave Plate Applications in Visible Frequencies

Abstract

Figure 5. Overlapping flakes: a) Schematic representation of the overlapping flakes along with the experimental setup. b) Photo of the overlapping flakes under study with marked regions I, II, and III representing respectively the bottom flake, top flake, and the overlapping region. c) The simulated and measured ratio of the cross-polarized to co-polarized transmittance for regions marked in (b) for flake rotation angle α = 68 ○ . The dashed line represents the case where there is no rotation between the flake axes (α = 0). d) Simulated spectral ellipticity (r) versus α. The green dotted line represents 500 nm data mark. e-g) The simulated and measured polar plots of reflectance as a function of analyzer angle (ϕ a ) when polarizer angle is kept constant at ϕ p = 45° at regions I, II, and III shown in (b) at 500 nm wavelength. The blue dashed line in (e)-(g) illustrates the source characterization at various ϕ a values when ϕ p = 45°. The insets in (e)-(g) are the respective polarization ellipses.

Configurable Phonon Polarization Responses in Twisted α-MoO3

“…Using the reported refractive indices, we calculate the interference enhancement factors of SVPM and TVPM for α-MoO 3 with different thicknesses on the SiO 2 /Si substrate excited by 532 and 633 nm, as shown in Figure S5 (for more calculated details, please see Part 3 in the Supporting Information). Compared to BP and b-As, , the enhancement factors of α-MoO 3 vary less with thickness, which may be attributed to the low extinction coefficient and refractive indices (close to 2) of α-MoO 3 . , When the thickness of α-MoO 3 is less than 50 nm, the enhancement factors decrease (increase) with thickness under 532 (633) nm excitation. The variation of the I of α-MoO 3 with thickness is most likely attributed to the enhancement factor.…”

“…It is reported that Δn equals 0.15 (0.12) under 532 (633) nm excitation. 46 For the tBL α-MoO 3 samples (∼28.0 nm), ϕ ac 532 = ∼2.84°and ϕ ac 633 = ∼1.91°. Such a small ϕ ac guarantees that the birefringence modulation is weak and can be ignored.…”

“…Compared to BP and b-As, 18,51 the enhancement factors of α-MoO 3 vary less with thickness, which may be attributed to the low extinction coefficient and refractive indices (close to 2) of α-MoO 3 . 46,52 When the thickness of α-MoO 3 is less than 50 nm, the enhancement factors decrease (increase) with thickness under 532 (633) nm excitation. The variation of the I of α-MoO 3 with thickness is most likely attributed to the enhancement factor.…”

“…It is estimated as ϕ a c = 2 π Δ n d λ , , where d is the thickness of α-MoO 3 sample and Δ n is the refractive index difference of α-MoO 3 along the [100] and [001] directions. It is reported that Δ n equals 0.15 (0.12) under 532 (633) nm excitation . For the tBL α-MoO 3 samples (∼28.0 nm), ϕ ac 532 = ∼2.84° and ϕ ac 633 = ∼1.91°.…”

Pressure driven structural phase transitions and modulations in optical properties of lanthanum nitride: an account from on the fly molecular dynamics and SCF vis-à-vis non-SCF first-principle calculations

“…The birefringence values for the P4/nmm phase of the system, as estimated from SCF (nSCF) calculation are found to be ∼1.99 (1.53), 2.03 (1.42) and 1.83 (1.15) at E M ∼ 1.8, 2 and 2.5 eV respectively. The high n D values for the above referred phase of the compound in the visible region of the EM wave (1.7 < E M < 3 eV) may be helpful in designing enhanced optoelectronic devices such as polarizing prisms, optic-axis gratings, light modulators and polaroids [94,[119][120][121][122].…”