J. Hamel

Simple technique for measuring the Goos–Hänchen effect with polarization modulation and a position-sensitive detector

An original approach to directly measuring the Goos-Hänchen longitudinal shift between TE and TM polarization states during a total internal reflection is introduced. The technique is based on the modulation of the polarization state of a laser by an electro-optic modulator combined with a precise measurement of the resulting spatial displacement with a position-sensitive detector. This method presents many advantages over other techniques and allows measurements at different wavelengths over a broad range for the incident angle.

Laser pumped 4He magnetometer

We describe the realization of a 4He magnetometer based on optical pumping with an optical frequency modulated laser diode light. Performances (amplitude and frequency spatial isotropy and sensitivity) of our device are presented and compared with those of other scalar magnetometers.

A new optical pumping scheme using a frequency modulated semi-conductor laser for 4He magnetometers

Abstract Recently, a distributed Bragg reflector (DBR) laser diode was developed by Spectra Diode Labs for helium optical pumping experiments. An interesting feature is the possibility of frequency modulation of the diode output by modulating the current intensity leading to a new pumping scheme, never reported before. An application to the realisation of very simple earth magnetometers without external modulators or external RF field is proposed.

4He optical pumping with polarization modulated light

Abstract In optical pumping experiments using a laser, beam polarization can be changed easily with the help of an electro-optic device. High frequency modulation of a LNA laser beam polarization has been used to pump 4 He (2 3 S 1 ) metastable atoms. New resonances, never observed before, have been studied theoretically and experimentally, and application to high sensitivity magnetometers is suggested.

Dispersive effects in optically pumped (2 3S1) 4He atomic vapor measured by using a geometrical optics technique

This paper describes an experiment where the Hanle effect and the double magnetic resonance in the metastable state of an atomic transition is detected, not by a modification of the light absorbed or reemitted by the atoms, but by a modification of the refractive index of the atomic vapor. The detection is based on the deflection of the optical pumping beam by a prismatic cell containing the gas and measured with the help of a position sensitive detector.

3He maser for earth magnetic field measurement

We describe the realization of a 3He Maser operating as an Earth magnetic field magnetometer. Preliminary experiments in order to optimize the device are first presented and finally the 3He Maser is used in the Earth magnetic field and compared with a 4He magnetometer.

Active mode-locked operation of a diode pumped colour-centre laser

Abstract The cw laser diode pumping of an (F + 2 ) ∗ colour centre laser has been recently demonstrated in our laboratory. The intensity of the pumping diode can easily be hf modulated. We present here the first experiments in which the colour centre laser is synchronously pumped at the mode spacing frequency, resulting in the emission of clean, regularly spaced pulses. The opto-electronic feedback is a very promising method of obtaining such a pulsed operation of a diode pumped colour centre laser without the use of an external hf oscillator.