Biomedical subjects

D D Yavuz

Publications and source records attributed to D D Yavuz.

6 recordsLinked to original sources

PubMed2006

Fast ground state manipulation of neutral atoms in microscopic optical traps.

We demonstrate Rabi flopping at MHz rates between ground hyperfine states of neutral 87Rb atoms that are trapped in two micron sized optical traps. Using tightly focused laser beams we demonstrate high fidelity, site specific Rabi rotations with cross talk on neighboring sites separated by 8 microm at the level of 10(-3). Ramsey spectroscopy is used to measure a dephasing time of 870 micros, which is approximately 5000 longer than the time for a pi/2 pulse.

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PubMed2005

Refractive index enhancement in a far-off resonant atomic system.

We demonstrate a scheme where a laser beam which is very far detuned from an atomic resonance experiences a large index of refraction with vanishing absorption. The essential idea is to excite two Raman resonances with appropriately chosen strong control lasers.

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PubMed2005

Generation of a single-cycle optical pulse.

We make use of coherent control of four-wave mixing to the ultraviolet as a diagnostic and describe the generation of a periodic optical waveform where the spectrum is sufficiently broad that the envelope is approximately a single-cycle in length, and where the temporal shape of this envelope may be synthesized by varying the coefficients of a Fourier series. Specifically, using seven sidebands, we report the generation of a train of single-cycle optical pulses with a pulse width of 1.6 fs, a pulse separation of 11 fs, and a peak power of 1 MW.

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PubMed2003

Quasiperiodic Raman technique for ultrashort pulse generation.

We report the experimental demonstration of a new Raman technique that produces 200 sidebands, ranging in wavelength from 3 microm to 195 nm. By studying multiphoton ionization of nitric oxide (NO) molecules, we show mutual phase coherence among 15 visible sidebands covering 0.63 octaves of bandwidth.

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PubMed2001

Femtosecond light source for phase-controlled multiphoton ionization.

We describe a femtosecond Raman light source with more than an octave of optical bandwidth. We use this source to demonstrate phase control of multiphoton ionization under conditions where ionization requires eleven photons of the lowest frequency of the spectrum or five photons of the highest frequency. The nonlinearity of the photoionization process allows us to characterize the light source. Experiment-to-theory comparison implies generation of a near single-cycle waveform.

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PubMed2000

Raman generation by phased and antiphased molecular states.

We use molecular deuterium and two driving lasers to demonstrate collinear generation of mutually coherent equidistant sidebands, covering 50 000 cm(-1) of spectral bandwidth and ranging from 2.94 microm to 195 nm in wavelength. The essential idea is the adiabatic preparation of a single, highly coherent (|rho(ab)| = 0.33) molecular eigenstate.

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