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A laser is not necessarily a sophisticated device: Pumping energy into an amplifying medium randomly filled with scatterers, a powder for instance, makes a perfect "random laser." In such a laser, the absence of mirrors greatly simplifies…

Optics · Physics 2015-06-15 N. Bachelard , S. Gigan , X. Noblin , P. Sebbah

Optical frequency combs (OFCs), consisting of a set of phase locked equally spaced laser frequency lines, have enabled a great leap in precision spectroscopy and metrology since seminal works of H\"ansch et al. . Nowadays, OFCs are…

We study spectral singularities of an infinite planar slab of homogeneous optically active material in focus of a thin lens under illumination of a Gaussian beam. We describe the field distribution of the Gaussian beam under this…

Optics · Physics 2022-12-14 Mehrdad Bavaghar , Rasoul Aalipour , Kazem Jamshidi-Ghaleh

The ultrafast dynamic evolution of an atomic system under medium-strength laser fields is studied by performing transient absorption measurement. An analytical model developed from perturbation theory with a modified transition dipole…

Atomic Physics · Physics 2019-05-22 Zhenhao Wang , Yu He , Quanjun Wang , Jingjie Ding , Shaohua Sun , Zuoye Liu , Bitao Hu

Spectral broadening of ultrashort laser pulses is simultaneously described by either self-phase modulation (SPM) or four-wave mixing (FWM). The latter implies the instantaneous conservation of both the photon number and energy, while the…

Optics · Physics 2018-06-18 Pierre Béjot , Jérôme Kasparian

Operation of a degenerate dual-pump phase sensitive amplifier (PSA) is thoroughly numerically investigated using a multi-wave model, taking into account high-order waves associated with undesired four-wave mixing (FWM) processes. More…

Optics · Physics 2016-01-20 Weilin Xie , Ihsan Fsaifes , Tarek Labidi , Fabien Bretenaker

Slow feature analysis (SFA), as a method for learning slowly varying features in classification and signal analysis, has attracted increasing attention in recent years. Recent probabilistic extensions to SFA learn effective representations…

Machine Learning · Computer Science 2025-09-10 Vishal Rishi

We perform high resolution spectroscopy of $N_2^+$ emission in light filaments using a controlled pump at 795 followed by a second harmonic weak probe. Our result suggests that transient gain is achieved by resonant stimulated Raman…

We report about investigations of time-dependent structural modifications in single crystal graphene due to laser irradiation even at moderate power levels of 1mW in a diffraction limited spot. The structural modifications have been…

The sensitivity of classical Raman spectroscopy methods, such as Coherent Anti-Stokes Raman spectroscopy (CARS) or Stimulated Raman spectroscopy (SRS), is ultimately limited by shot-noise from the stimulating fields. We present the complete…

Optics · Physics 2021-10-22 Yoad Michael , Leon Bello , Michael Rosenbluh , Avi Pe'er

An internal field induced resonant intensity enhancement of Raman scattering of phonon excitations in InAs nanowires is reported. The experimental observation is in good agreement with the simulated results for the scattering of light under…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 Jaya Kumar Panda , Anushree Roy , Achintya Singha , Mauro Gemmi , Daniele Ercolani , Vittorio Pellegrini , Lucia Sorba

This work investigates single-photon scattering in a one-dimensional coupled-resonator waveguide coupled to a giant atom with a complex on-site energy. Within the generalized projection operator formalism, we derive analytical expressions…

Quantum Physics · Physics 2025-12-22 Yu Xin , Jia-Ming Zhang , Bing Chen

Fast radio bursts (FRBs), especially those from repeating sources, exhibit a rich variety of morphologies in their dynamic spectra (or waterfalls). Characterizing these morphologies and spectro-temporal properties is a key strategy in…

High Energy Astrophysical Phenomena · Physics 2025-11-26 Mohammed A. Chamma , Victor Pop , Fereshteh Rajabi

We measured the ensemble-averaged spectral correlation functions and statistical distributions of spectral spacing and intensity for lasing modes in weakly scattering systems, and compared them to those of the amplified spontaneous emission…

Optics · Physics 2009-11-13 Xiaohua Wu , Hui Cao

In the phased-array radar (PAR) signals from each antenna are transmitted at the same carrier frequency, which yields narrowly focused only angle dependent beampattern. In contrast, in the frequency-diverse-array (FDA) radar signals from…

Signal Processing · Electrical Eng. & Systems 2020-06-24 Muhammad Zubair , Sajid Ahmed , Mohamed-Slim Alouini

Optical frequency comb devices have unlocked new capabilities in telecommunications, sensing, and metrology. Yet, precise in situ control of the comb spectral envelope remains extremely challenging. By introducing mode coupling with…

We analyze the spectral evolution of 62 bright Fermi gamma-ray bursts with large enough signal to noise to allow for time resolved spectral analysis. We develop a new algorithm to test for single-pulse morphology that is insensitive to the…

High Energy Astrophysical Phenomena · Physics 2024-08-28 Ian Busby , Davide Lazzati

Stimulated Raman scattering (SRS) represents a powerful tool for accessing the vibrational properties of molecular compounds or solid state systems. From a spectroscopic perspective, SRS is able to capture Raman spectra free from incoherent…

This paper investigates relaying schemes in an amplify-and-forward multiple-input multiple-output relay network, where an energy-constrained relay harvests wireless power from the source information flow and can be further aided by an…

Information Theory · Computer Science 2016-05-12 Yang Huang , Bruno Clerckx

The optical spectrum of a quantum system is jointly determined by the properties of the emitter and the driving field. All-optical spectral control can hence be a promising method to engineer the properties of single photon emitters for…