Parallel self-mixing imaging system based on an array of vertical-cavity surface-emitting lasers

Tucker, J. R.; Baque, Johnathon L.; Lim, Yah Leng; Zvyagin, Andrei V.; Rakić, Aleksandar D.

doi:10.1364/ao.46.006237

Cited by 20 publications

(9 citation statements)

References 34 publications

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“…While not outperforming existing photodetection techniques, the advantage of SMD is the easy way to make a very sensitive back-reflection detector, capable of detecting echoes down to about −90 dB of the outgoing power [7], [9]. On the other hand, the SMD scheme becomes a real breakthrough when we handle signals for which photodiodes are much less efficient or not be readily available, like at THz frequency [9], [33].…”

Section: Description Of Weak Feedbackmentioning

confidence: 99%

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The Diagram of Feedback Regimes Revisited

Donati

Horng

2013

IEEE J. Select. Topics Quantum Electron.

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We revisit the well-known Tkach and Chraplyvy (T-C) diagram of feedback regimes in semiconductor lasers. Our aim is twofold: first, extending the classification of feedback effects in the T-C diagram to short and long external cavities, and to coherent and incoherent interactions; second and more important, identifying in the diagram feedback phenomena that have been meanwhile studied and developed to noteworthy applications, namely, self-mixing, period-1 and multiperiodicity, intermittency and chaos. We complement the feedback diagram with application regions, so as to describe not only feedback effects detrimental to a laser used as the transmitter of an optical link, but also feedback effects in the weak and strong regime of interaction, developed into applications for instrumentation and communications in recent years

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Section: Description Of Weak Feedbackmentioning

confidence: 99%

“…This is due to the self-mixing process in a semiconductor laser, not only affecting field amplitude E, but also carrier concentration N and hence voltage V [9], [33].…”

Section: Description Of Weak Feedbackmentioning

confidence: 99%

The Diagram of Feedback Regimes Revisited

Donati

Horng

2013

IEEE J. Select. Topics Quantum Electron.

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“…To our knowledge, a theoretical analysis of self-mixing signals from living tissues has not been developed yet due to the complicated structure of the self-mixing effect and the living tissues [19]. Despite that, M0 and M1 will be evaluated as M1 was previously evaluated by other authors [25,27].…”

Section: Power Spectrum Methodsmentioning

confidence: 99%

Self-mixing microprobe for monitoring microvascular perfusion in rat brain

Figueiras

Oliveira

Lourenço

et al. 2012

Med Biol Eng Comput

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Measuring functional activity in brain in connection with neural stimulation faces technological challenges. Our goal is to evaluate, in relative terms, the real-time variations of local cerebral blood flow in rat brain, with a convenient spatial resolution. The use of laser Doppler flowmetry (LDF) probes is a promising approach but commercially available LDF probes are still too large (450 lm) to allow insertion in brain tissue without causing damage in an extension that may negatively impact local measurements. The self-mixing technique coupled to LDF is herein proposed to overcome limitations of the minimal diameter of the probe imposed by non-self-mixing probes (commercial available probes). Our Monte Carlo simulations show that laser photons have a mean penetration depth of 0.15 mm, on the rat brain with the 785 nm laser light microprobe. Moreover, three self-mixing signal processing methods are tested: counting method, autocorrelation method, power spectrum method. The perfusion signal computed shows a good linearity with the scatterers velocity, for the three methods (a determination coefficient close to one is obtained), for the in vitro measurements. Furthermore, we believe that these indicators can be used to monitor local blood flow changes in the rat brain.

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“…To achieve this, a 24 channel monolithic VCSEL array imaging system was proposed by the previous group members [192,193] and electronic parts such as a 24 channel driver including the receiver, and amplifier were designed and built. As a part of my PhD I tested and characterized the VCSEL array, measured the light-current and voltage-current curves for the channels, measured SNRs of the channels under different current operations, determined optimized operational currents to gain the best SNR from the channels, investigated the thermal behavior of the array by installing thermistors next to the array, installed electric triggering of the channels, conducted the noise characterization of the channels, was involved in mounting the laser array head on x-y-z translation stages, created LabVIEW software to control and run the system and save the signals in a PC, tested and automated the software to control the currents of the array, and performed signal processing, amongst other work.…”

Section: Chapter 7 7 Parallel Laser Imagingmentioning

confidence: 99%

“…This would not only increase the spatial resolution of an imaging system based on this array, but also allow for a smaller lens to be used due to the smaller array size, making the whole optical system more compact.The temperature rise in the array may also be increased by increasing the element diameter as suggested by Osinski et al [204]. However, larger diameter VCSELs may exhibit multiple transverse modes, which can affect the accuracy and performance of SM sensors [193].…”

Section: Introductionmentioning

confidence: 98%

Skin cancer detection using laser imaging

Mowla¹

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Endeavors to develop a non-invasive and reliable device to detect different types of skin cancer in its early stages have been undertaken over the past few years. Although some advances have been made towards such developments, there remains great scope for the development of a non-expensive, compact, reliable, safe, easy to use, fast, sensitive, and non-invasive device. This project will apply the innovative laser feedback interferometry (LFI) technique to skin cancer detection via laser imaging using near-infrared vertical cavity surface emitting lasers (VCSELs). In this project, the science behind lighttissue interactions has been explored and skin imaging modalities have been elaborately studied. As a result, LFI has been exploited in various configurations to image different modalities such as Doppler flowmetry and confocal reflectance. In addition to single modality imaging, dual-modality imaging has also been proposed and conducted experimentally, to image Doppler flowmetry and confocal reflectance at the same time, using an integrated LFI system. It is shown that dual-modality imaging can yield images with higher contrast which provide more information about morphological and functional characteristics of a target under test.In addition to two-dimensional LFI imaging, three-dimensional imaging systems have also been studied and employed in the laboratory. A tomographic image identifies tissue volume with altered optical properties due to cancerous or other malignant tissue processes. We applied the three-dimensional imaging system to different types of keratinocyte skin cancer phantoms and results show high level of sensitivity in providing tomographic images. Using high numerical aperture lenses, making images at resolutions down to micrometer scales is possible, which is promising for microscopy of biological structures.Furthermore, parallel LFI imaging using an array of 24 VCSELs was also studied theoretically and experimentally as a part of this work. A VCSEL array was used in a parallel read-out LFI imaging system to develop a fast and high resolution device, which eliminates the need to scan mechanically in one dimension.Investigating the complex interactions of the laser beam and tissue requires a powerful and robust simulation technique. Monte Carlo was used as a simulation technique to model the light-tissue interactions occurring in the optical systems in this work. Firstly, we tested and validated the Monte Carlo main engine which was developed in the group, by studying morphological aspects of the simulated and experimental signals in a laser Doppler velocimetry system, and deep insight into the nature of the LFI Doppler spectrum and further conclusions were drawn. Secondly, the Monte Carlo engine was used in iii modeling and analyzing of optical systems, in this work.We developed tissue phantom making techniques which were used to examine the experimental ideas in place of biological samples which are difficult to obtain and work with. Therefore, tissue phantom techniques were studie...

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Parallel self-mixing imaging system based on an array of vertical-cavity surface-emitting lasers

Cited by 20 publications

References 34 publications

The Diagram of Feedback Regimes Revisited

The Diagram of Feedback Regimes Revisited

Self-mixing microprobe for monitoring microvascular perfusion in rat brain

Skin cancer detection using laser imaging

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