Gambhir Ranjit

Attonewton force detection using microspheres in a dual-beam optical trap in high vacuum

We describe the implementation of laser-cooled silica microspheres as force sensors in a dual-beam optical dipole trap in high vacuum. Using this system we have demonstrated trap lifetimes exceeding several days, attonewton force detection capability, and wide tunability in trapping and cooling parameters. Measurements have been performed with charged and neutral beads to calibrate the sensitivity of the detector. This work establishes the suitability of dual beam optical dipole traps for precision force measurement in high vacuum with long averaging times, and enables future applications including the study of gravitational inverse square law violations at short range, Casimir forces, acceleration sensing, and quantum opto-mechanics.

Measurement of7p1/2-state hyperfine structure and7s1/2-7p1/2transition isotope shift in203Tl and205Tl

A two-step, two-color laser spectroscopy technique has been used to measure the hyperfine splitting of the 7p

Measurement of the scalar polarizability within the 5P1/2-6S1/2410-nm transition in atomic indium

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Cold atoms as a coolant for levitated optomechanical systems

excited state in

Extended tuning of an injection-locked diode laser

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Photoassociative Spectroscopy of Ultracold Metastable Argon

Tl and

Precision sensing and hybrid opto-mechanics with optically-levitated nanoparticles

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Testing gravity at the micron scale using optically trapped nanospheres

Tl, as well as the isotope shift within the 7s

Ultra-sensitive force sensing with optically levitated nanospheres

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Cold atoms coupled to nano-mechanical systems

- 7p