The dynamical response of a laser to frequency-shifted optical feedback is investigated both theoretically and experimentally. The ultrahigh sensitivity of a class-B laser (i.e., a laser with a cavity damping rate ${\ensuremath{\gamma}}_{c}$ higher than the population damping rate ${\ensuremath{\gamma}}_{1})$ to external light injection is demonstrated by the optical detection of weak optical feedback. Compared to a conventional optical beating, the intensity modulation induced by the coherent interaction between the laser electric field and the frequency-shifted reinjected electric field can be several orders of magnitude higher. This method permits high sensitive interferometry and hence imaging. We call this laser detection technique laser optical feedback imaging (LOFI). When the optical frequency shift is resonant with the laser relaxation frequency, the intracavity amplification of the beating is maximum and the enhancement is given by the laser damping rate ratio ${\ensuremath{\gamma}}_{c}/{\ensuremath{\gamma}}_{1}.$ This amplification is of the order of ${10}^{6}$ for a microchip laser. We also show that without optical feedback the strong fluctuations of the laser output power are well described by the Langevin noise process. In a broad range around the laser relaxation frequency the laser quantum noise is also resonantly amplified and is then several orders of magnitude higher than the detector noise. In these conditions, the LOFI is a shot noise limited detection technique. Reflectivity as low as ${10}^{\ensuremath{-}13}$ is then easily detectable with a laser output power of a few milliwatts with a detection bandwidth of 1 kHz. Experimentally, for weak optical feedback the laser fluctuations are principally composed of the LOFI modulation signal at the shifted frequency and of the laser quantum noise amplified at the relaxation frequency. For strong optical feedback, nonlinear effects appear in the laser dynamics. In these conditions, harmonics and parametrics peaks appear in the power spectrum. The LOFI detection system is then saturated.The dynamical response of a laser to frequency-shifted optical feedback is investigated both theoretically and experimentally. The ultrahigh sensitivity of a class-B laser (i.e., a laser with a cavity damping rate ${\ensuremath{\gamma}}_{c}$ higher than the population damping rate ${\ensuremath{\gamma}}_{1})$ to external light injection is demonstrated by the optical detection of weak optical feedback. Compared to a conventional optical beating, the intensity modulation induced by the coherent interaction between the laser electric field and the frequency-shifted reinjected electric field can be several orders of magnitude higher. This method permits high sensitive interferometry and hence imaging. We call this laser detection technique laser optical feedback imaging (LOFI). When the optical frequency shift is resonant with the laser relaxation frequency, the intracavity amplification of the beating is maximum and the enhancement is given by the laser damping rate ratio ${\ensuremath{\gamma}}_{c}/{\ensuremath{\gamma}}_{1}.$ This amplification is of the order of ${10}^{6}$ for a microchip laser. We also show that without optical feedback the strong fluctuations of the laser output power are well described by the Langevin noise process. In a broad range around the laser relaxation frequency the laser quantum noise is also resonantly amplified and is then several orders of magnitude higher than the detector noise. In these conditions, the LOFI is a shot noise limited detection technique. Reflectivity as low as ${10}^{\ensuremath{-}13}$ is then easily detectable with a laser output power of a few milliwatts with a detection bandwidth of 1 kHz. Experimentally, for weak optical feedback the laser fluctuations are principally composed of the LOFI modulation signal at the shifted frequency and of the laser quantum noise amplified at the relaxation frequency. For strong optical feedback, nonlinear effects appear in the laser dynamics. In these conditions, harmonics and parametrics peaks appear in the power spectrum. The LOFI detection system is then saturated.

Physical Review ASep 19, 2001134 citations

LASERS AND QUANTUM OPTICS

Lorenzo M. Narducci, Eduardo Jaime Quel, Jorge R. Tredicce

Apr 1, 19908 citations

Output coupling in optical cavities and lasers : a quantum theoretical approach

紀公雄氏原

1 A one-dimensional optical cavity with output coupling-classical analysis- 2 A one-dimensional optical cavity with output coupling-quantum analysis- 3 A one-dimensional quasimode laser: General formulation 4 A one-dimensional quasimode laser-Semiclassical and quantum analysis- 5 A one-dimensional laser with output coupling -Derivation of the laser equation of motion- 6 A one-dimensional laser with output coupling-Contour integral method- 7 A one-dimensional laser with output coupling-Semiclassical linear gain analysis 8 A one-dimensional laser with output coupling-Semiclassical nonlinear gain analysis 9 A one-dimensional laser with output coupling-Quantum linear gain analysis- 10 A one-dimensional laser with output coupling -Quantum nonlinear gain analysis- 11 Analysis of a one-dimensional laser with two-side output coupling -The propagation method- 12 A one-dimensional laser with output coupling -Summary and interpretation of the results- 13 Spontaneous emission in a one-dimensional optical cavity with output coupling 14 Theory of excess noise 15 Quantum theory of the output coupling of an optical cavity Appendices1 A one-dimensional optical cavity with output coupling-classical analysis- 2 A one-dimensional optical cavity with output coupling-quantum analysis- 3 A one-dimensional quasimode laser: General formulation 4 A one-dimensional quasimode laser-Semiclassical and quantum analysis- 5 A one-dimensional laser with output coupling -Derivation of the laser equation of motion- 6 A one-dimensional laser with output coupling-Contour integral method- 7 A one-dimensional laser with output coupling-Semiclassical linear gain analysis 8 A one-dimensional laser with output coupling-Semiclassical nonlinear gain analysis 9 A one-dimensional laser with output coupling-Quantum linear gain analysis- 10 A one-dimensional laser with output coupling -Quantum nonlinear gain analysis- 11 Analysis of a one-dimensional laser with two-side output coupling -The propagation method- 12 A one-dimensional laser with output coupling -Summary and interpretation of the results- 13 Spontaneous emission in a one-dimensional optical cavity with output coupling 14 Theory of excess noise 15 Quantum theory of the output coupling of an optical cavity Appendices

Wiley-VCH eBooksJan 1, 20102 citations

Quantum Optics and Light

S. Chua

Springer thesesJan 1, 20150 citations

Study of the Vulnerability of Neutral Optical Filters Used in Quantum Key Distribution Systems against Laser Damage Attack

S. V. Alferov, Kirill E. Bugai, Паргачёв Иван Андреевич

Quantum key distribution systems are accessible to an eavesdropper; i.e., the eavesdropper can attack not only quantum states but also the equipment. In the former case, vulnerabilities are removed by fundamental constraints (e.g., no-cloning theorem) or theoretical foundations for their removal exist. In the latter case, vulnerability is determined by the practical implementation of equipment. An attack with laser damage of optical components called laser damage attack can allow the eavesdropper to reduce the attenuation of optical elements and compromise distributed keys. In this work, a method based on neutral optical filters has been described for protection from laser damage attack against optical components. A scheme imitating actions of the eavesdropper in the process of laser damage attack has been presented. An approach has been proposed to calculate the parameters of optical elements after the attack. Processes occurring in samples exposed to intense laser radiation have been analyzed. The analysis of experimental data has indicated the stability and constraints of neutral optical filters used in quantum key distribution systems for protection from laser damage attack.Quantum key distribution systems are accessible to an eavesdropper; i.e., the eavesdropper can attack not only quantum states but also the equipment. In the former case, vulnerabilities are removed by fundamental constraints (e.g., no-cloning theorem) or theoretical foundations for their removal exist. In the latter case, vulnerability is determined by the practical implementation of equipment. An attack with laser damage of optical components called laser damage attack can allow the eavesdropper to reduce the attenuation of optical elements and compromise distributed keys. In this work, a method based on neutral optical filters has been described for protection from laser damage attack against optical components. A scheme imitating actions of the eavesdropper in the process of laser damage attack has been presented. An approach has been proposed to calculate the parameters of optical elements after the attack. Processes occurring in samples exposed to intense laser radiation have been analyzed. The analysis of experimental data has indicated the stability and constraints of neutral optical filters used in quantum key distribution systems for protection from laser damage attack.

Journal of Experimental and Theoretical Physics LettersJul 1, 20228 citations

Quantum optics

Stefan Tappertzhofen, Jack Alexander-Webber

Elsevier eBooksOct 17, 20250 citations

{10}^{6}

for a microchip laser. We also show that without optical feedback the strong fluctuations of the laser output power are well described by the Langevin noise process. In a broad range around the laser relaxation frequency the laser quantum noise is also resonantly amplified and is then several orders of magnitude higher than the detector noise. In these conditions, the LOFI is a shot noise limited detection technique. Reflectivity as low as ${10}^{\ensuremath{-}13}$ is then easily detectable with a laser output power of a few milliwatts with a detection bandwidth of 1 kHz. Experimentally, for weak optical feedback the laser fluctuations are principally composed of the LOFI modulation signal at the shifted frequency and of the laser quantum noise amplified at the relaxation frequency. For strong optical feedback, nonlinear effects appear in the laser dynamics. In these conditions, harmonics and parametrics peaks appear in the power spectrum. The LOFI detection system is then saturated.