H S Rawat
Articles written in Pramana – Journal of Physics
Volume 65 Issue 3 September 2005 pp 403-411
Laser frequency stabilization and large detuning by Doppler-free dichroic lock technique: Application to atom cooling
V B Tiwari S R Mishra H S Rawat S Singh S P Ram S C Mehendale
We present results of a study of frequency stabilization of a diode laser (λ = 780 nm) using the Doppler-free dichroic lock (DFDL) technique and its use for laser cooling of atoms. Quantitative measurements of frequency stability were performed and the Allan variance was found to be 6.9 × 1011 for an averaging time of 10 s. The frequency-stabilized diode laser was used to obtain the trapping beams for a magneto-optic trap (MOT) for Rb atoms. Using the DFDL technique, the laser frequency could be locked over a wide range and this enabled measurement of detuning dependence of the number and temperature of cold atoms using a relatively simple experimental set-up.
Volume 82 Issue 2 February 2014 pp 419-423 Contributed Papers
Optimization of transfer of laser-cooled atom cloud to a quadrupole magnetic
S P Ram S K Tiwari S R Mishra H S Rawat
We present here our experimental results on transfer of laser-cooled atom cloud to a quadrupole magnetic trap. We show that by choosing appropriately the ratio of potential energy in magnetic trap to kinetic energy of cloud in molasses, we can obtain the maximum phase-space density in the magnetic trap. These results guide us to choose the value of current to be switched in the quadrupole coils used for magnetic trapping for a given temperature of the cloud after molasses. This study is also useful to set the initial phase-space density of the cloud before evaporative cooling.
Volume 83 Issue 1 July 2014 pp 131-138
The effect of laser beam size in a zig-zag collimator on transverse cooling of a krypton atomic beam
Vivek Singh V B Tiwari S Singh S R Mishra H S Rawat
The effect of size of a cooling laser beam in a zig-zag atomic beam collimator on transverse cooling of a krypton atomic beam is investigated. The simulation results show that discreteness in the interaction between the cooling laser beam and atomic beam, arising due to finite size and incidence angle of the cooling laser beam, significantly reduces the value of transverse velocity capture range of the collimator. The experimental observations show the trend similar to that obtained from simulations. Our study can be particularly useful where a small zig-zag collimator is required.
Volume 97, 2023
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