Photoelastic modulator for polarimetry and ellipsometry

Canit, J. C.; Badoz, J.

doi:10.1364/ao.23.002861

Cited by 16 publications

(6 citation statements)

References 2 publications

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“…-First, we select the 3p 1 region around 17 360 cm -1 since it is fairly well isolated and no spurious effects were observed. Our simulated curves (for v2/vl = 4.3) are shown on figure 13. A comparison with figure 6 indicates that the overall experimental profiles are well reproduced.…”

Section: Incommensuratementioning

confidence: 58%

“…We verified the absence of stray signal in zero field and corrected the data for the rate of depolarization as measured by placing an optically active sample (camphorquinone in dioxane) before and after the crystal investigated. MCD spectra were taken with standard equipment, i.e., a photoelastic modulator [13] and a phase sensitive detector. Measurements at 4.2 K and below (pumped helium) were made with a superconducting magnet (2.5 T or 5 T).…”

Section: Low Lying Doubletmentioning

confidence: 99%

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Spectroscopic study of the incommensurate phase of ThBr4 via the optical and magnetooptical properties of U4+

et al. 1985

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U4+ is used to probe the incommensurate structure of ThBr 4 via absorption and magnetic circular dichroism (MCD) measurements. Below Tc = 95 K, the crystal field experienced by U 4+ ions is either of D2d or D2 symmetry. This can be simulated by varying a phase angle ϕ form 0(D 2d) to ± π/2 (D2). One very neat advantage of MCD over absorption is that the D2d centres show up very clearly in the former due to the occurrence of a derivative-like singularity. We present a model to simulate absorption, Zeeman and MCD profiles. It accounts satisfactorily for most of our data and we arrive at the following main conclusions : (i) it is probable that the phase is truly incommensurate since the lower limit of the number of sites is found to be 80; (ii) for a low concentration of U4+ (2 x 10-4), we found no evidence of a pinning of the incommensurate modulation by the impurities. MCD provides also a definite proof that the ground state of U 4+ in ThBr4 is Γ4 with a D2 d symmetry. Finally, we determine the Landé factors of five excited states, our findings being in fair agreement with the results of recent crystal field calculations

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Section: Incommensuratementioning

confidence: 58%

Section: Low Lying Doubletmentioning

confidence: 99%

Spectroscopic study of the incommensurate phase of ThBr4 via the optical and magnetooptical properties of U4+

et al. 1985

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“…Instrumental techniques such as photoelastic modulation coupled with synchronous detection [22,23] currently make possible highly precise polarimetric and ellipsometric measurements within the IR, visible, and UV regions of the spectrum. In principle there should be no insuperable obstacles to the advancement of comparable polarimetric methods for microwave frequencies.…”

Section: -Spin-associated Rotational Optical Activitymentioning

confidence: 99%

Optical activity induced by rotation of atomic spin

Silverman

1992

Il Nuovo Cimento D

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Physical systems or processes invariant under mirror reflection are not expected to exhibit intrinsically chiral asymmetries. Thus, it is ordinarily the case that unbounded and unexcited atoms (in the absence of weak nuclear interactions) should not manifest circular birefringence. It is shown, however, that in a rotating reference frame the coupling of atomic spin angular momentum to the angular velocity of the rest frame gives to optical activity even in the absence of contributions from nuclear interactions and the classical Coriolis force. Ground-state atomic hydrogen is predicted to be optically active in the microwave region near the hyperfine splitting frequency of 1420 MHz. Under appropriate circumstances, this spin-associated rotational circular birefringence can be some ten orders of magnitude larger than that previously estimated for virtual electronic transitions failing within the visible and UV portions of the spectrum.PACS 31.90 -Other topics in the theory of the electronic structure of atoms and molecules (including properties other than the energy). PACS 03.65 -Quantum theory; quantum mechanics.

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“…Single frequency polarization modulators find use in applications such as polarimetry, ellipsometry, polarization spectroscopy, linear and circular dichroism, and as optical choppers. [1][2][3][4][5][6][7][8][9][10][11] Polarization modulators are typically constructed using acousto-optic devices that are referred to as photoelastic modulators. These modulators consist of an isotropic material bonded to a piezoelectric transducer.…”

Section: Introductionmentioning

confidence: 99%

Optically isotropic longitudinal piezoelectric resonant photoelastic modulator

Atalar,

Arbabian

2024

Photonic Instrumentation Engineering XI

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Photoelastic modulators are widely used optical instruments across many applications. Despite being in use since the 1960s, their design has remained largely unchanged. The main limitation of these modulators is the fundamental trade-off between the input aperture and the modulation frequency. These modulators typically operate around 50 kHz modulation frequency for centimeter square scale apertures. Optically isotropic and piezoelectric crystals, like gallium arsenide, gallium phosphide, zinc selenide, and zinc sulfide offer a groundbreaking opportunity to create new kinds of photoelastic modulators to overcome this trade-off. By adopting this new design, we can achieve both high modulation frequencies (in the megahertz frequency regime) and large input apertures (centimeter square scale) simultaneously.

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Photoelastic modulator for polarimetry and ellipsometry

Cited by 16 publications

References 2 publications

Spectroscopic study of the incommensurate phase of ThBr4 via the optical and magnetooptical properties of U4+

Spectroscopic study of the incommensurate phase of ThBr4 via the optical and magnetooptical properties of U4+

Optical activity induced by rotation of atomic spin

Optically isotropic longitudinal piezoelectric resonant photoelastic modulator

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