Generation of terahertz (THz) radiation has been a hot research topic in recent years. Plasmonic quantum cascade lasers (QCLs) are among the most compact and efficient sources to generate THz radiation. In this paper, we comprehensively study plasmonic QCLs designed based on antenna-feedback structure about center frequency 3 THz. By changing geometric cavity using two-dimensional simulation, m...

The frequency-dependent group delay of dielectric mirrors was measured by spectrally resolved white-light interferometry. Chirped mirrors and thin-film Gires-Tournois interferometers designed for dispersion control in a femtosecond Ti:sapphire laser oscillator-amplifier system were tested with a group-delay resolution of +/-0.2 fs and a spectral resolution of ~1 nm over the spectral range of 67...

We demonstrate passive mode-locking of a Raman fiber laser using a nanotube-based saturable absorber coupled to a net normal dispersion cavity. This generates highly chirped 500 ps pulses. These are then compressed down to 2 ps, with 1.4 kW peak power, making it a simple wavelength-versatile source for various applications.

A mode-locked Raman laser, using 25 m of a GeO2 doped fiber as the gain medium, is reported employing carbon nanotubes. The oscillator generates 850 ps chirped pulses, which are externally compressed to 185 ps. OCIS codes: (060.2310) Fiber optics; (140.3550) Lasers, Raman

An apparatus that utilizes buffer gas cooling to produce slow atomic (Ba, Ca) and molecular (BaF, CaF) beams is constructed. In-cell temperatures of 20 0.25K are achieved with chamber cooldown times of under two hours. Laser Induced Fluorescence (LIF) spectra of BaF and CaF confirmed thermalization of the molecular beam to the temperature of the buffer gas and additional hydrodynamic cooling to...

We demonstrate self-starting 6.5-fs pulses from a Kerr-lens mode-locked Ti:sapphire laser with 200-mW average output power at a pulse repetition rate of ~86 M Hz. This is to our knowledge the shortest pulse ever generated directly from a laser. For dispersion compensation we used a prism pair in combination with double-chirped mirrors, which balances the higher-order dispersion of the prism pai...

An ABCD formalism is identified to characterize a seeded Free Electron Laser (FEL) with three chirps: an initial frequency chirp in the seed Laser, an energy chirp in the electron bunch, and an intrinsic frequency chirp due to the FEL process. A scheme of generating attosecond few-cycle pulses is proposed by invoking an FEL seeded by high-order harmonic generation (HHG) from an infrared laser. ...

In this paper we present a prototype instrument for remote open-path detection of nitrous oxide. The sensor is based on a 4.53 μm quantum cascade laser and uses the chirped laser dispersion spectroscopy (CLaDS) technique for molecular concentration measurements. To the best of our knowledge this is the first demonstration of open-path laser-based trace-gas detection using a molecular dispersion...

The development and characterization of a diode-pumped ultrashort pulse Yb:KGd(WO(4))(2) laser oscillator is reported. The laser was pumped by a 25W fiber-coupled diode laser module operating at 980 nm wavelength. In the mode-locked regime, 296 fs duration pulses centered around 1031 nm were generated at a repetition rate of 61 MHz with a total average output power of up to 3.7W, corresponding ...

We present a method of producing single attosecond pulses by high order harmonic generation with multi-cycle nonlinear chirped driver laser pulses. The symmetry of the laser field in several optical cycles near the pulse center is dramatically broken, and then the photons which cover a much broad spectrum burst almost only in one optical cycle. So an ultra-broad continuum spectrum appears in th...