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Laser feedback

Measurement of the emission spectrum of a semiconductor laser using laser-feedback interferometry

Measurement of the emission spectrum of a semiconductor laser using laser-feedback interferometry

... optical feedback OF in lasers have been observed since the early days of laser development While OF can result in undesirable and unpredictable operation in laser systems it can also cause measurable ...

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Coherent imaging using laser feedback interferometry with pulsed-mode terahertz quantum cascade lasers

Coherent imaging using laser feedback interferometry with pulsed-mode terahertz quantum cascade lasers

... Laser feedback interferometry, also known as SM interferometry, is a coherent sensing scheme that employs a laser as a homodyne ...transceiver. Laser feedback interferometry relies on ...

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Simple Electrical Modulation Scheme for Laser Feedback Imaging

Simple Electrical Modulation Scheme for Laser Feedback Imaging

... the laser beam by acousto-optic deflec- tors [9]–[11] or swept-frequency feedback interferometry with directly modulated lasers ...the laser carrier, by measuring the extremely small variations in ...

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THz QCL self-mixing interferometry for biomedical applications

THz QCL self-mixing interferometry for biomedical applications

... In this paper, we introduce the self-mixing phenomenon in terahertz quantum cascade lasers (THz QCLs) and present recent advancements in the development of coherent THz imaging and sensing systems that exploit the ...

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Model for a pulsed terahertz quantum cascade laser under optical feedback

Model for a pulsed terahertz quantum cascade laser under optical feedback

... [4–7]. Laser feedback interferometry (LFI) with THz QCLs is a recently-developed coherent sensing technique [8–10], ideally-suited to the development of compact sensing sys- tems, in which radiation is ...

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A model for a pulsed terahertz quantum cascade laser under optical feedback

A model for a pulsed terahertz quantum cascade laser under optical feedback

... [4–7]. Laser feedback interferometry (LFI) with THz QCLs is a recently-developed coherent sensing technique [8–10], ideally-suited to the development of compact sensing sys- tems, in which radiation is ...

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Laser Diodeexcitationsystem Controlled By Software For Photothermal Applications

Laser Diodeexcitationsystem Controlled By Software For Photothermal Applications

... the laser diode and this can be done by placing a second divider of beam after the first splitter (beam splitter), such that you may use a computer model and verify Newport optical intensity to get the ...

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Single-mode surface-emitting concentric-circular-grating terahertz quantum cascade lasers

Single-mode surface-emitting concentric-circular-grating terahertz quantum cascade lasers

... In conclusion, we have demonstrated single-mode sur- face emitting THz QCLs using second-order CCGs, which can be simply fabricated by metal evaporation on top of the laser active region. We have achieved a ...

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Free-space optics mode-wavelength division multiplexing system using LG modes based on decision feedback equalization

Free-space optics mode-wavelength division multiplexing system using LG modes based on decision feedback equalization

... A FSO MWDM system of seven Laguerre-Gaussian (LG) modes based on DFE has been simulated in OptSim [26] and exhibited illustratively in Fig. 1. The FSO MWDM system consists of three parts; transmitter, FSO channel, and ...

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Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser

Three-dimensional terahertz imaging using swept-frequency feedback interferometry with a quantum cascade laser

... Coherent 3D imaging was demonstrated using exemplar GaAs structures [9] that were fabricated by wet chemical etching. The sample comprised three stepped regions (in the X-direction) with a nominal step height 10 µm and a ...

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An Improved Design for an All Optical Flip Flop Based on a Nonlinear 3 Sections DFB Laser Cavity

An Improved Design for an All Optical Flip Flop Based on a Nonlinear 3 Sections DFB Laser Cavity

... disk laser where the two states correspond to clock-wise and anti-clock-wise mode is ...micro laser rings is implemented in [3]. Flip-flop based on a single DFB laser structure is shown in ...

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The Optoelectronic Swept-Frequency Laser and Its Applications in Ranging, Three-Dimensional Imaging, and Coherent Beam Combining of Chirped-Seed Amplifiers

The Optoelectronic Swept-Frequency Laser and Its Applications in Ranging, Three-Dimensional Imaging, and Coherent Beam Combining of Chirped-Seed Amplifiers

... So far we have assumed an SFL with a perfectly sinusoidal electric field. Practical lasers, however, exhibit phase and frequency noise. These fluctuations arise due to both external causes, such as thermal fluctuations, ...

177

Inducing tunable single-mode operation of Fabry-Perot semiconductor laser coupled with very-short cavity with selective optical feedback

Inducing tunable single-mode operation of Fabry-Perot semiconductor laser coupled with very-short cavity with selective optical feedback

... the laser supports single-mode oscillation by subjecting the laser to very strong optical feedback and avoiding the chaotic state [28, ...semiconductor laser coupled with a very-short external ...

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Wide-bandwidth mode-hop-free tuning of extended-cavity GaN diode lasers

Wide-bandwidth mode-hop-free tuning of extended-cavity GaN diode lasers

... parent ( ⬃ 40 pm 兾 °C) as the overall mode pattern is shifting to the right. In Fig. 4(b) the corresponding plot for the 410 nm FP laser is shown. There are several distinct differences compared to the behavior of ...

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Laser chemosensor with rapid responsivity and inherent memory based on a polymer of intrinsic microporosity

Laser chemosensor with rapid responsivity and inherent memory based on a polymer of intrinsic microporosity

... We have demonstrated that the polymer PIM-1 is a good chemosensor for detecting low vapor pressure (~10 ppb) DNB vapor. Successful indication of the presence of the analyte, by monitoring the photoluminescence has been ...

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Nonlinear Dynamics in Directly Modulated Semiconductor Lasers with Optical Loop Mirror Feedback

Nonlinear Dynamics in Directly Modulated Semiconductor Lasers with Optical Loop Mirror Feedback

... NOLM feedback systems are plotted for time series on the left-hand side of Figures 2(a)-(e), and the phase por- traits on the right-hand side of the ...optical feedback and modula- tion ...

5

Stable Single Mode Operation of Distributed Feedback Quantum Cascade Laser by Optimized Reflectivity Facet Coatings

Stable Single Mode Operation of Distributed Feedback Quantum Cascade Laser by Optimized Reflectivity Facet Coatings

... the laser core so that thermal effect restrained another mode lasing and mode hop would not ...DFB laser that an antireflection (AR) coating has been deposited on its front facet, and we choose an AR ...

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Optical Nerve Detection by Diffuse Reflectance Spectroscopy for Feedback Controlled Oral and Maxillofacial Laser Surgery

Optical Nerve Detection by Diffuse Reflectance Spectroscopy for Feedback Controlled Oral and Maxillofacial Laser Surgery

... control laser ablation in surgery, the computational time required for analyzing the reflectance spectra is ...basic feedback system was established with an acoustic sensor by our workgroup showing the ...

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Feedback Control Theory - Free Computer, Programming, Mathematics, Technical Books, Lecture Notes and Tutorials

Feedback Control Theory - Free Computer, Programming, Mathematics, Technical Books, Lecture Notes and Tutorials

... It is also important to realize at the outset that practical problems have uncertain, non- minimum-phase plants (non-minimum-phase means the existence of right half-plane zeros, so the inverse is unstable); that there ...

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Frontline Employee Feedback-Seeking Behavior: How Is It Formed and When Does It Matter?

Frontline Employee Feedback-Seeking Behavior: How Is It Formed and When Does It Matter?

... perceived feedback-seeking climate on ...seek feedback due to a lack of resources ...positive feedback-seeking climate can help alleviate such challenges by providing the necessary resources and ...

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