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We demonstrate third harmonic generation in plasmonic antennas made of highly doped germanium and designed to be resonant in the mid infrared. Owing to the near-field enhancement, the result is an ultrafast, sub-diffraction, coherent light…
We calculate, via variational techniques, single- and two-photon Rydberg microwave transitions, as well as scalar and tensor polarizabilities of sodium atom using the parametric one-electron valence potential, including the spin-orbit…
We use two continuous-wave (CW) laser beams of 780 nm and 515 nm to optically drive $^{85}$Rb atoms in a heated vapor cell to a low-lying Rydberg state 10D$_{5/2}$. We observe a collimated ultraviolet (UV) beam at 311 nm, corresponding to…
We demonstrate an efficient scheme for the generation of broadband, high-energy, circularly polarized femtosecond laser pulses in the deep ultraviolet through seeded degenerate four-wave mixing in stretched gas-filled hollow capillary…
Filamentation of ultrashort laser pulses in the atmosphere offers unique opportunities for long-range transmission of high-power laser radiation and standoff detection. With the critical power of self-focusing scaling as the laser…
We investigate spontaneous radiative processes in a driven polar two-level system whose interaction with the laser field is dominated by broken inversion symmetry rather than by the usual transition dipole coupling. Using a polaron…
We report on spiking dynamics of frequency up-converted emission at 420 nm generated on the 6P3/2-5S1/2 transition in Rb vapour two-photon excited to the 5D5/2 level with laser light at 780 and 776 nm. The spike duration is less than the…
Optical parametric amplification is a second-order nonlinear process whereby an optical signal is amplified by a pump via the generation of an idler field. It is the key ingredient of tunable sources of radiation that play an important role…
We present the generation of THz radiation by focusing ultrafast laser pulses with three incommensurate wavelengths to form a plasma. The three colors include 800 nm and the variable IR signal and idler outputs from an optical parametric…
We report on studies of simultaneous continuous-wave mirrorless lasing on multiple optical transitions, realized by pumping hot cesium vapor with laser light resonant with the 6$S_{1/2}\rightarrow 8$P$_{3/2}$ transition. The multiplicity of…
Laguerre-Gauss beams, and more generally the orbital angular momentum of light (OAM) provide valuable research tools for optical manipulation, processing, imaging and communication. Here we explore the high-efficiency frequency conversion…
Experimental spectroscopic studies are presented, in a 5.5--25.5nm extreme-ultraviolet (EUV) wavelength range, of the light emitted from plasma produced by the irradiation of tin microdroplets by 5-ns-pulsed, 2-$\mu$m-wavelength laser…
We report the first observation of free-electron angular momentum wave packets generated by atomic multiphoton ionization with bichromatic three-dimensional (3D) polarization-tailored ultrashort laser fields. These fields, created by the…
Electromagnetic scattering in accelerating reference frames inspires a variety of phenomena, requiring employment of general relativity for their description. While the quasi-stationary field analysis could be applied to slowly-accelerating…
The mid-infrared (MIR) spectral range is of immense use for civilian and military applications. The large number of vibrational absorption bands in this range can be used for gas sensing, process control and spectroscopy. In addition, there…
All-optical Compton sources combine laser wakefield accelerators and intense scattering pulses to generate ultrashort bursts of backscattered radiation. The scattering pulse plays the role of a short-period undulator in which relativistic…
We have developed and demonstrated a versatile, compact electron source that can produce a monoenergetic electron beam up to 50 mm diameter from 0.1 to 30 keV with an energy spread of <10 eV. By illuminating a metal cathode plate with a…
We discuss nonlinear spectra of selective reflection from high-density rubidium atomic vapor, where the self-broadening of the resonant transition $5S_{1/2}-5P_{3/2}$ dominates over the Doppler width. In the experiments, the hole-burning…
It has been known for quite some time that spinning polygon, and similar, swept lasers used in OCT favor the short to long wavelength sweep direction because of four wave mixing in the gain medium. Here we have reformulated the problem in…
We describe a superconducting device capable of producing laser light in the visible range at half of the Josephson generation frequency with the optical phase of the light locked to the superconducting phase difference. It consists of two…