Amplified sensing of optical phase difference through the phase of the resultant field

Athira, T S; Naik, Dinesh N.

doi:10.1088/2040-8986/ac213e

Cited by 2 publications

(2 citation statements)

References 16 publications

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“…Where 𝜙 12 = 𝜙 1 − 𝜙 2 , the phase difference between the individual phases 𝜙 1 and 𝜙 2 , of interfering fields 𝐸 1 (𝜔) and 𝐸 2 (𝜔). The phase of the superposed field 𝐸 𝑆 = 𝐸 1 (𝜔) + 𝐸 2 (𝜔) varies with path delay, according to the ratio of amplitudes of interfering beam 𝛼 = |𝐸 1 |/|𝐸 2 | and the beam which is phase shifted as discussed in 7 . To study the phase variation an additional field 𝐸 3 (𝜔) is required.…”

Section: Theorymentioning

confidence: 99%

Sensitivity enhancement in low coherence Fourier transform spectral interferometry

Athira

Naik

2023

Women in Optics and Photonics in India 2022

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In conventional interferometry, the intensity of the superposed field is observed to study the phase information of object / sample field. The schemes like Weak measurement scheme, spectral switching observes the intensity of the output field for enhancing the sensitivity of the phase measurements. A scheme to enhance the sensitivity in the measurement of path delays through spectral interferometry by observing the phase accumulated by the superposed field with respect to an additional reference beam is presented. Through the interference with additional reference beam maintained at out-of-phase condition near zero optical path delay with respect to the sample probe beam, it is shown to introduce nonlinearity in phase change measured. In the experimental demonstration, the classic low coherence spectral interferometry is used. The three-beam interference is achieved by a modified Michelson interferometer. According to the setting of initial path delay and amplitude ratio of the interfering fields, the intensity of superposed field shows spectral modulations. Spectral phase is measured from the modulations in the recorded spectral interference using Fourier transform method of fringe analysis. In the Fourier domain, a linear path delay between in the interfering beams gives a linear shift in the position of secondary peak. By filtering the secondary peak from the Fourier domain, and taking the Inverse Fourier transform, the amplitude and phase information of the interfering fields can be obtained. The proposed method maps the linear path delay to highly nonlinear phase accumulation and has the potential to enhance sensitivity of phase measurements.

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Section: Theorymentioning

confidence: 99%

Sensitivity enhancement in low coherence Fourier transform spectral interferometry

Athira

Naik

2023

Women in Optics and Photonics in India 2022

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“…For a > 1, the phase values keep increasing beyond p 2 which in turn gets wrapped up between the range [ ] p p -, .Hence the phase is unwrapped to obtain a variation as shown in figure2(c). The distinct behaviour of the phase for the two settings of α hints at the lifting of degeneracy in contribution to phase from f 1 and f 2 as described in equation (5)[16].To study the nonlinearity in the phase accumulated by the superposed field, the spectral intensities| | E s 2obtained from the simulation for the path delay l figure 3(a) are analysed. The amplitude ratio α is set to 1.02.…”

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confidence: 99%

Nonlinear phase accumulation for a linear path delay in low coherence fourier transform spectral interferometry

Athira

Naik

2023

Phys. Scr.

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A scheme to measure path delay in spectral interferometry by observing the phase accumulated by the superposed field is presented. Through the interference with an additional reference beam maintained at an out-of-phase condition near zero optical path delay with respect to the sample probe beam, a nonlinearity in measured phase is observed. A detailed simulation is presented, and its experimental proof-of concept demonstration is attempted using the classic low coherence spectral interferometry. The spectral phase is measured from the modulations in the recorded spectral interference using Fourier transform method of fringe analysis. A systematic calibration for setting up the experiment even with unknown parameters like amplitude ratio among the interfering fields, and location of the zero optical path delay is also provided

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Amplified sensing of optical phase difference through the phase of the resultant field

Cited by 2 publications

References 16 publications

Sensitivity enhancement in low coherence Fourier transform spectral interferometry

Sensitivity enhancement in low coherence Fourier transform spectral interferometry

Nonlinear phase accumulation for a linear path delay in low coherence fourier transform spectral interferometry

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