Joshua C. Vaughan
Massachusetts Institute of Technology
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Publication
Featured researches published by Joshua C. Vaughan.
Optics Letters | 2004
Gabriel Popescu; Lauren P. DeFlores; Joshua C. Vaughan; Kamran Badizadegan; Hidenao Iwai; Ramachandra R. Dasari; Michael S. Feld
By use of the Fourier decomposition of a low-coherence optical image field into two spatial components that can be controllably shifted in phase with respect to each other, a new high-transverse-resolution quantitative-phase microscope has been developed. The technique transforms a typical optical microscope into a quantitative-phase microscope, with high accuracy and a path-length sensitivity of lambda/5500, which is stable over several hours. The results obtained on epithelial and red blood cells demonstrate the potential of this instrument for quantitative investigation of the structure and dynamics associated with biological systems without sample preparation.
Optics Letters | 2005
Joshua C. Vaughan; Thomas Hornung; Thomas Feurer; Keith A. Nelson
A new diffraction-based method is proposed and demonstrated for simultaneous shaping of both the phase and amplitude of femtosecond laser pulses by use of a phase-only two-dimensional spatial light modulator. The method suppresses certain types of temporal replica features ordinarily observed in femtosecond pulse shaping owing to imperfections in modulator devices and allows for multiplexed outputs suitable for use in various applications.
Optics Express | 2006
Joshua C. Vaughan; Thomas Feurer; Katherine W. Stone; Keith A. Nelson
We present a detailed analysis of commonly encountered waveform distortions in femtosecond pulse shaping with pixelated devices, including the effects of discrete sampling, pixel gaps, smooth pixel boundaries, and nonlinear dispersion of the laser spectrum. Experimental and simulated measurements are used to illustrate the effects. The results suggest strategies for reduction of some classes of distortions.
Optics Letters | 2004
Thomas Hornung; Joshua C. Vaughan; Thomas Feurer; Keith A. Nelson
We report noncollinear, degenerate four-wave mixing experiments that employ a new device based on two-dimensional femtosecond pulse shaping that delays and modulates all incident fields. Heterodyne detection is easily implemented due to the full phase stability of the device.
Optics Letters | 2002
Thomas Feurer; Joshua C. Vaughan; Richard M. Koehl; Keith A. Nelson
We report the automated generation of high-fidelity spatiotemporally shaped femtosecond pulses by use of an optically addressed, two-dimensional liquid-crystal spatial light modulator. A single input pulse was divided into many independent regions, and each region was shaped temporally. By changing the imaging geometry we accomplished either real-space or wave-vector shaping.
Optics Letters | 2004
Thomas Feurer; Joshua C. Vaughan; Thomas Hornung; Keith A. Nelson
We demonstrate programmable generation of temporally shaped terahertz waveforms in LiNbO3 by spatially shaping the beam profile of femtosecond excitation laser pulses with a spatial light modulator. The generated terahertz waveforms have amplitudes that are approximately proportional to the first spatial derivative of the excitation beam profile.
Optics Letters | 2003
Joshua C. Vaughan; Thomas Feurer; Keith A. Nelson
We exploit the close similarities between time-frequency and position-wave-vector correspondences to control the spatiotemporal diffraction pattern of ultrashort laser pulses. This approach permits novel, automated generation of sophisticated two-dimensional femtosecond waveforms. A two-dimensional space-time version of a Gerchberg-Saxton algorithm is used to iteratively determine the phase pattern in position-frequency space that produces a user-defined intensity profile in wave-vector-time space.
lasers and electro-optics society meeting | 2006
Ka-Lo Yeh; Eric R. Statz; Joshua C. Vaughan; Thomas Hornung; Keith A. Nelson
The tools of THz polaritonics are extended for improved polariton amplification and for nonlinear THz spectroscopy using amplified and focused polariton waveforms. THz coherent spectroscopy and control applications are enabled
15th International Conference on Ultrafast Phenomena (2006), paper FA3 | 2006
Katherine W. Stone; Thomas Hornung; Joshua C. Vaughan; Keith A. Nelson
Multidimensional optical spectroscopy of potassium dimer is demonstrated using a 2D femtosecond pulse shaper with excellent phase stability. Coherent control of intramolecular dynamics is achieved by introducing specific pulse sequences and chirps.
Springer series in chemical physics | 2005
Thomas Hornung; Joshua C. Vaughan; Thomas Feurer; Keith A. Nelson
Degenerate, noncollinear, optically heterodyned, spectrally resolved, multidimensional femtosecond χ(3) measurements are executed with waveforms, delays, and spectral phases and amplitudes of all fields controlled by a single active device in a fully phase matched beam geometry.