The laser feedback interferometer

Clunie, D.; Rock, Nicholas

doi:10.1088/0950-7671/41/8/301

Cited by 26 publications

(6 citation statements)

References 4 publications

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“…e laser intensity modulation caused by the movable external mirror is similar to that generated by the traditional optical interferometer [39]. When the feedback mirror moves at the distance of half of the laser wavelength, the fringes will be produced.…”

Section: Laser Feedback Interferometrymentioning

confidence: 83%

Research Progress of Stress Measurement Technologies for Optical Elements

Wei

Pang

Bai

et al. 2021

International Journal of Optics

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It is of great significance to measure the residual stress distribution accurately for optical elements and evaluate its influence on the performance of optical instruments in optical imaging, aviation remote sensing, semiconductor manufacturing, and other fields. The stress of optical elements can be closely related to birefringence based on photoelasticity. Thus, the method of quantifying birefringence to obtain the stress becomes the main method of stress measurement technologies for optical elements. This paper first introduces the basic principle of stress measurement based on photoelasticity. Then, the research progress of stress measurement technologies based on this principle is reviewed, which can be classified into two methods: polarization method and interference method. Meanwhile, the advantages and disadvantages of various stress measurement technologies are analyzed and compared. Finally, the developing trend of stress measurement technologies for optical elements is summarized and prospected.

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Section: Laser Feedback Interferometrymentioning

confidence: 83%

Research Progress of Stress Measurement Technologies for Optical Elements

Wei

Pang

Bai

et al. 2021

International Journal of Optics

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“…Laser self-mixing velocimetry is a compact, versatile laser Doppler velocimetry technique to determine the velocity or vibratory motion of reflecting surfaces e.g. in biomedical and structural sensing and yields high accuracy and resolution in practical applications [1][2][3][4][5]. In laser interferometry the light from the interferometer reference arm and the Doppler-shifted light reflected from the moving reflector interfere resulting in a velocity-dependent Doppler frequency [6].…”

Section: Introductionmentioning

confidence: 99%

Two-state semiconductor laser self-mixing velocimetry exploiting coupled quantum-dot emission-states: experiment, simulation and theory

Gioannini

Dommermuth²,

Drzewietzki³

et al. 2014

Opt. Express

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We exploit the coupled emission-states of a single-chip semiconductor InAs/GaAs quantum-dot laser emitting simultaneously on ground-state (λ(GS) = 1245 nm) and excited-state (λ(ES) = 1175 nm) to demonstrate coupled-two-state self-mixing velocimetry for a moving diffuse reflector. A 13 Hz-narrow Doppler beat frequency signal at 317 Hz is obtained for a reflector velocity of 3 mm/s, which exemplifies a 66-fold improvement in width as compared to single-wavelength self-mixing velocimetry. Simulation results reveal the physical origin of this signal, the coupling of excited-state and ground-state photons via the carriers, which is unique for quantum-dot lasers and reproduce the experimental results with excellent agreement.

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“…Factors that affect the light re-entering the laser include the reflectivity of the object, which determines the optical amplitude and the total optical pathlength transmitted by the re-entry light, which in turn determines the optical phase. This phenomenon allows the construction of a minimum-component interferometer, a laser-feedback interferometer (Clunie & Rock, 1964), consisting of a laser, the object whose surface topography and reflectivity properties are to be measured, and a photodetector to monitor the laser light intensity (O'Neill et al, 1991;Bearden et al, 1993;JuSkaitis et al, 1992JuSkaitis et al, , 1993. In order to incorporate LFI principles into a scanning confocal microscope, we consider the response of the laser light intensity to changes in target position and reflectivity, and the effect of target oscillation.…”

Section: Introductionmentioning

confidence: 99%

PHOEBE, a prototype scanning laser‐feedback microscope for imaging biological cells in aqueous media

Wong

Sabato

Bearden

1995

Journal of Microscopy

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SUMMARY Based on the principle of laser‐feedback interferometry (LFI), a laser‐feedback microscope (LFM) has been constructed capable of providing an axial (z) resolution of a target surface topography of ∼ 1 nm and a lateral (x, y) resolution of ∼ 200 nm when used with a high‐numerical‐aperture oil‐immersion microscope objective. LFI is a form of interferometry in which a laser's intensity is modulated by light re‐entering the illuminating laser. Interfering with the light circulating in the laser resonant cavity, this back‐reflected light gives information about an object's position and reflectivity. Using a 1‐mW He–Ne (λ = 632·8 nm) laser, this microscope (PHOEBE) is capable of obtaining 256 × 256‐pixel images over fields from (10 μm × 10 μm) to (120 μm × 120 μm) in ∼ 30 s. An electromechanical feedback circuit holds the optical pathlength between the laser output mirror and a point on the scanned object constant; this allows two types of images (surface topography and surface reflectivity) to be obtained simultaneously. For biological cells, imaging can be accomplished using back‐reflected light originating from small refractive‐index changes (> 0·02) at cell membrane/water interfaces; alternatively, the optical pathlength through the cell interior can be measured point‐by‐point by growing or placing a cell suspension on a higher‐reflecting substrate (glass or a silicon wafer). Advantages of the laser‐feedback microscope in comparison to other confocal optical microscopes include: the simplicity of the single‐axis interferometric design; the confocal property of the laser‐feedback microscope (a virtual pinhole), which is achieved by the requirement that only light that re‐enters the laser meeting the stringent frequency, spatial (TEM00), and coherence requirements of the laser cavity resonator mode modulate the laser intensity; and the improved axial resolution, which is based on interferometric measurement of optical amplitude and phase rather than by use of a pinhole as in other types of confocal microscopes.

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The laser feedback interferometer

Cited by 26 publications

References 4 publications

Research Progress of Stress Measurement Technologies for Optical Elements

Research Progress of Stress Measurement Technologies for Optical Elements

Two-state semiconductor laser self-mixing velocimetry exploiting coupled quantum-dot emission-states: experiment, simulation and theory

PHOEBE, a prototype scanning laser‐feedback microscope for imaging biological cells in aqueous media

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