Axial Mode Number of Gas Lasers from Moving-Mirror Experiments

Peek, Th.H.; Bolwijn, Piet; Alkemade, C.Th.J.

doi:10.1119/1.1974260

Cited by 40 publications

(10 citation statements)

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“…These multiple reflections may be modeled as a change in the effective reflectivity of the laser mirror such that the measured intensity may be written as Eq. (4) [26, 28, 29]:

I_{i} = I_{o} {1 + A cos (φ + ψ_{i}) + B cos (φ + θ + ψ_{i})}

In the “sample-free” region, the parameters { A , ϕ } in Eq. (4) represent the visibility and accumulated phase associated with the weak reflections from the optics along the path (“background term”) and the parameters { B , θ } represent the subsequent reflection that occurs after the partially transmitted field is reflected from the coverslip-buffer interface (“signal term”).…”

Section: Modeling the Visibility And Optical Path Lengthmentioning

confidence: 99%

Reflectivity and topography of cells grown on glass-coverslips measured with phase-shifted laser feedback interference microscopy

Atılgan

Ovryn

2011

Biomed. Opt. Express

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In spite of the advantages associated with the molecular specificity of fluorescence imaging, there is still a significant need to augment these approaches with label-free imaging. Therefore, we have implemented a form of interference microscopy based upon phase-shifted, laser-feedback interferometry and developed an algorithm that can be used to separate the contribution of the elastically scattered light by sub-cellular structures from the reflection at the coverslip-buffer interface. The method offers an opportunity to probe protein aggregation, index of refraction variations and structure. We measure the topography and reflection from calibration spheres and from stress fibers and adhesions in both fixed and motile cells. Unlike the data acquired with reflection interference contrast microscopy, where the reflection from adhesions can appear dark, our approach demonstrates that these regions have high reflectivity. The data acquired from fixed and live cells show the presence of a dense actin layer located ≈ 100 nm above the coverslip interface. Finally, the measured dynamics of filopodia and the lamella in a live cell supports retrograde flow as the dominate mechanism responsible for filopodia retraction.

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“…These multiple reflections may be modeled as a change in the effective reflectivity of the laser mirror such that the measured intensity may be written as Eq. (4) [26, 28, 29]:

I_{i} = I_{o} {1 + A cos (φ + ψ_{i}) + B cos (φ + θ + ψ_{i})}

Section: Modeling the Visibility And Optical Path Lengthmentioning

confidence: 99%

Reflectivity and topography of cells grown on glass-coverslips measured with phase-shifted laser feedback interference microscopy

Atılgan

Ovryn

2011

Biomed. Opt. Express

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“…Based on existing theories [25][26][27], the varied optical frequency is approximately expressed as:…”

Section: Methodsmentioning

confidence: 99%

“…However, the magnitude of refraction index change due to environmental disturbance of experiment room is at 10e-6 level, which means the refraction index variation induces a pico-meter level uncertainty to micron vibration measurement. Based on laser physics of single mode 632.8nm He-Ne laser [26] [30], optical laser frequency [31] is a terahertz quantity with a stable short-time uncertainty. Therefore, the relative variation of wavelength Δλ is about 10e-7 level.…”

Section: Emdwtmentioning

confidence: 99%

Carrier-separating demodulation of phase shifting self-mixing interferometry

Tao¹,

Wang²,

Xia³

2017

Optics & Laser Technology

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A carrier separating method associated with noise-elimination had been introduced into a sinusoidal phase-shifting selfmixing interferometer. The conventional sinusoidal phase shifting self-mixing interferometry was developed into a more competitive instrument with high computing efficiency and nanometer accuracy of λ/100 in dynamical vibration measurement. The high slew rate electro-optic modulator induced a sinusoidal phase carrier with ultralow insertion loss in this paper. In order to extract phase-shift quickly and precisely, this paper employed the carrier-separating to directly generate quadrature signals without complicated frequency domain transforms. Moreover, most noises were evaluated and suppressed by a noiseelimination technology synthesizing empirical mode decomposition with wavelet transform. The overall laser system was described and inherent advantages such as high computational efficiency and decreased nonlinear errors of the established system were demonstrated. The experiment implemented on a high precision PZT (positioning accuracy was better than 1nm) and compared with laser Doppler velocity meter. The good agreement of two instruments shown that the short-term resolution had improved from 10nm to 1.5nm in dynamic vibration measurement with reduced time expense. This was useful in precision measurement to improve the SMI with same sampling rate. The proposed signal processing was performed in pure timedomain requiring no preprocessing electronic circuits.

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“…Often considered as a parasitic phenomenon, it can for example drive the laser in a chaotic regime [1]. When it is correctly controlled, the optical re-injection in a laser can, however, be used in order to improve its characteristics, such as the lindwidth narrowing [2], or for metrology purpose [3][4][5][6][7][8], thus conferring on the laser the role of source and detector at the same time. Since 1963, this principle was employed in an autodyne configuration to measure distances or speeds [9,10].…”

Section: Introductionmentioning

confidence: 99%