We present a simple method for diode laser frequency stabilization that makes use of a Doppler-broadened vapor cell absorption signals of two frequency-shifted laser beams. Using second-order-diffracted, double-passed beams from an acousto-optic modulator, we achieve a frequency separation roughly equal to the Doppler half width. The differential transmission signals of the two beams provide an...

For the construction of high-precision optical assemblies, direction and position measurement and control of the involved laser beams are essential. While optical components such as beamsplitters and mirrors can be positioned and oriented accurately using coordinate measuring machines (CMMs), the position and direction control of laser beams is a much more intriguing task since the beams cannot...

We study the influence of two resonant laser beams (to be referred to as the control and probe beams) on the centre of mass motion of ultra-cold atoms characterised by three energy levels of the Λ-type. The laser beams being in the Electromagnetically Induced Transparency (EIT) configuration drive the atoms to their dark states. We impose the adiabatic approximation and obtain an effective equa...

Lasers can be used for the generation of high brightness electron and exotic ion beams, the acceleration of particles with the highest accelerating gradients, as well as for the characterization of many complex particle beams by means of laser-based beam Diagnostics methods. In addition, (free electron) lasers can be used for achieving the highest time resolution and strongest fields for experi...

High-power, ultrashort laser pulses have been shown to generate quasi-monoenergetic electron beams from underdense plasmas. Several groups have reported generating high-energy electron beams using either supersonic nozzles or a capillary based system to guide the laser pulse. While, significant progress has been achieved in the last several years, many issues still remain, with respect to point...

We have proposed a new method of generating highly polarized positrons through Compton scattering of polarized laser lights o! relativistic electron beams and successive pair creation. To realize high-luminosity laser}electron collisions, we constructed a specially designed chamber which equips o!-axis parabolic mirrors with a through hole at the center. This mirror achieves strong focusing of ...

The optical sensor is composed of two eyesafe parallel laser beams operating at two different wavelengths (see Figure 1). When a vehicle passes in front of the sensor, the laser light is diffused on the surface of the vehicle. The diffused light is then focused on two photodetectors, one for each laser. We thus obtain two signals, x(t) and yet), which represent the fluctuations in time of the i...

Multimode laser operation is usually characterized by high output power, yet its beam quality is inferior to that of a laser with single TEM00 mode operation. Here we present an efficient approach for improving the beam quality of multimode laser resonators. The approach is based on splitting the intra-cavity multimode beam into an array of smaller beams, each with a high quality beam distribut...

The ability to dynamically shape the spatial intensity profile of an incident laser beam enables new ways to modify and structure surfaces through pulsed laser processing. Here we describe a method to generate doughnutshaped beams from an input Gaussian source using a tunable acoustic gradient index (TAG) lens. The TAG lens is capable of modulating between focused beams and annular rings of var...

Ionization-induced injection mechanism was introduced in 2010 to reduce the laser intensity threshold for controllable electron trapping in laser wakefield accelerators (LWFA). However, usually it generates electron beams with continuous energy spectra. Subsequently, a dual-stage target separating the injection and acceleration processes was regarded as essential to achieve narrow energy-spread...