Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 10 of 10
Full-Text Articles in Physics
Supercontinuum Generation With A Ti: Sapphire Laser And Photonic Crystal Fiber, Joseph Lange
Supercontinuum Generation With A Ti: Sapphire Laser And Photonic Crystal Fiber, Joseph Lange
Celebrating Scholarship and Creativity Day (2018-)
A broad spectrum of visible light was produced by focusing the 50-fs, 800-nm, 5-nJ pulses from an unamplified Ti:sapphire laser into a 20-cm-long photonic crystal fiber. A prism pair was used to compensate for material dispersion of the system. Different focusing methods were investigated including beam telescopes and lenses of various focal lengths. A 3X beam expander telescope near the laser output and a 3-cm focal length achromatic lens after the prism pair were found to work best for coupling the light into the fiber which has a core diameter of 1.7 μm.
Comparison Of The Fluorescence Of Bulk Cadmium Sulfide And Cadmium Sulfide Nanoparticles, Jacob Goranson
Comparison Of The Fluorescence Of Bulk Cadmium Sulfide And Cadmium Sulfide Nanoparticles, Jacob Goranson
Celebrating Scholarship and Creativity Day (2018-)
The fluorescence of bulk cadmium sulfide and cadmium sulfide nanoparticles were compared. This was done using an 800-nm, unamplified Ti:sapphire laser producing 50-fs pulses. The pulses were frequency doubled using a beta barium borate (BBO) crystal. The 400-nm beam was used to induce fluorescence in the nanoparticles, while the original 800-nm beam was used to induce fluorescence in the bulk CdS by two-photon absorption. The bulk CdS showed a single fluorescent peak at 523 nm. The nanoparticles showed fluorescence at various wavelengths across the visible spectrum. In general, the nanoparticles showed a broad fluorescent spectrum between 500 nm and 750 …
Two-Photon Absorption And Fluorescence Of Cadmium Sulfide, Jacob Goranson, Gregory J. Taft
Two-Photon Absorption And Fluorescence Of Cadmium Sulfide, Jacob Goranson, Gregory J. Taft
Physics Faculty Publications
The two-photon absorption and fluorescence of bulk cadmium sulfide were studied using 50-fs, 800-nm pulses from an unamplified Ti:sapphire laser. The fluorescence spectrum was measured to have a main peak at 522 nm, and the power of the fluorescence was shown to vary quadratically with the 800-nm beam power. This supports the theory that the fluorescence is excited by two-photon absorption and confirms previous work done with longer duration, higher energy excitation pulses. Pump-probe measurements provided additional confirmation of the two-photon absorption. Measured spectral broadening of the wings of the laser spectrum also was observed, which likely is due to …
Transient Transmission Oscillations In Doped And Undoped Lithium Niobate Induced By Near-Infrared Femtosecond Pulses, Bryan J. Crossman, Gregory J. Taft
Transient Transmission Oscillations In Doped And Undoped Lithium Niobate Induced By Near-Infrared Femtosecond Pulses, Bryan J. Crossman, Gregory J. Taft
Physics Faculty Publications
Transient transmission oscillations in X-cut and Z-cut congruent, iron-doped, and magnesium-doped lithium niobate samples were measured using 50 fs, 800 nm, 0.5 nJ pulses from a self-mode-locked Ti:sapphire laser in an optical pump–probe system. Several Raman-active oscillation modes excited by these pulses were observed as changes in the transmitted probe intensity versus time delay between the pump and probe pulses. The samples were rotated to determine how the incident polarization of the pump pulses affects the mode excitations. The observed Raman-active oscillations correspond to previously reported symmetry modes measured with traditional, continuous-wave, Raman spectroscopy using the same scattering …
Mid-Infrared Optical Frequency Combs Based On Difference Frequency Generation For Molecular Spectroscopy, Flavio C. Cruz, Daniel L. Maser, Todd Johnson, Gabriel Ycas, Andrew Klose, Fabrizio R. Giorgetta, Ian Coddington, Scott A. Diddams
Mid-Infrared Optical Frequency Combs Based On Difference Frequency Generation For Molecular Spectroscopy, Flavio C. Cruz, Daniel L. Maser, Todd Johnson, Gabriel Ycas, Andrew Klose, Fabrizio R. Giorgetta, Ian Coddington, Scott A. Diddams
Physics Faculty Publications
Mid-infrared femtosecond optical frequency combs were produced by difference frequency generation of the spectral components of a near-infrared comb in a 3-mm-long MgO:PPLN crystal. We observe strong pump depletion and 9.3 dB parametric gain in the 1.5 μm signal, which yields powers above 500 mW (3 μW/mode) in the idler with spectra covering 2.8 μm to 3.5 μm. Potential for broadband, high-resolution molecular spectroscopy is demonstrated by absorption spectra and interferograms obtained by heterodyning two combs.
Mid-Infrared Upconversion Spectroscopy Based On A Yb:Fiber Femtosecond Laser, Todd Johnson, Scott A. Diddams
Mid-Infrared Upconversion Spectroscopy Based On A Yb:Fiber Femtosecond Laser, Todd Johnson, Scott A. Diddams
Physics Faculty Publications
We present a system for molecular spectroscopy using a broadband mid-infrared laser with near-infrared detection. Difference frequency generation of a Yb:fiber femtosecond laser produced a mid-infrared (MIR) source tunable from 2100–3700 cm-1 (2.7–4.7 μm) with average power up to 40 mW. The MIR spectrum was upconverted to near-infrared wavelengths for broadband detection using a two-dimensional dispersion imaging technique. Absorption measurements were performed over bandwidths of 240 cm-1 (7.2 THz) with 0.048 cm-1 (1.4 GHz) resolution, and absolute frequency scale uncertainty was better than 0.005 cm-1 (150 MHz). The minimum detectable absorption coefficient per spectral element was …
High-Power Broadband Laser Source Tunable From 3.0 Μm To 4.4 Μm Based On A Femtosecond Yb:Fiber Oscillator, Tyler W. Neely, Todd A. Johnson, Scott A. Diddams
High-Power Broadband Laser Source Tunable From 3.0 Μm To 4.4 Μm Based On A Femtosecond Yb:Fiber Oscillator, Tyler W. Neely, Todd A. Johnson, Scott A. Diddams
Physics Faculty Publications
We describe a tunable broadband mid-IR laser source based on difference-frequency mixing of a 100 MHz femto second Yb:fiber laser oscillator and a Raman-shifted soliton generated with the same laser. The resulting light is tunable over 3.0 μm to 4.4 μm, with a FWHM bandwidth of 170 nm and maximum average output power up to 125 mW. The noise and coherence properties of this source are also investigated and described.
Impact Of Dispersion On Amplitude And Frequency Noise In A Yb-Fiber Laser Comb, Lora Nugent-Glandorf, Todd A. Johnson, Yohei Kobayashi, Scott A. Diddams
Impact Of Dispersion On Amplitude And Frequency Noise In A Yb-Fiber Laser Comb, Lora Nugent-Glandorf, Todd A. Johnson, Yohei Kobayashi, Scott A. Diddams
Physics Faculty Publications
We describe a Yb-fiber-based laser comb, with a focus on the relationship between the net-cavity dispersion and frequency noise on the comb. While tuning the net-cavity dispersion from anomalous to normal, we measure the relative intensity noise, offset frequency (fCEO) linewidth, and the resulting frequency noise spectrum on the fCEO. We find that the laser operating at zero net-cavity dispersion has many advantages, including an approximately 100× reduction in free-running fCEO linewidth and frequency noise power spectral density when compared to the normal-dispersion regime. At the zero-dispersion point, we demonstrate a phase-locked fCEO …
Demonstration Of A Neutral Atom Controlled-Not Quantum Gate, L. Isenhower, E. Urban, X. L. Zhang, A. T. Gill, T. Henage, Todd A. Johnson, T. G. Walker, M. Saffman
Demonstration Of A Neutral Atom Controlled-Not Quantum Gate, L. Isenhower, E. Urban, X. L. Zhang, A. T. Gill, T. Henage, Todd A. Johnson, T. G. Walker, M. Saffman
Physics Faculty Publications
We present the first demonstration of a CNOT gate between two individually addressed neutral atoms. Our implementation of the CNOT uses Rydberg blockade interactions between neutral atoms held in optical traps separated by >8 μm. Using two different gate protocols we measure CNOT fidelities of F=0.73 and 0.72 based on truth table probabilities. The gate was used to generate Bell states with fidelity F=0.48±0.06. After correcting for atom loss we obtain an a posteriori entanglement fidelity of F=0.58.
Fast Ground State Manipulation Of Neutral Atoms In Microscopic Optical Traps, D. D. Yavuz, P. B. Kulatunga, E. Urban, Todd A. Johnson, N. Proite, T. Henage, T. G. Walker, M. Saffman
Fast Ground State Manipulation Of Neutral Atoms In Microscopic Optical Traps, D. D. Yavuz, P. B. Kulatunga, E. Urban, Todd A. Johnson, N. Proite, T. Henage, T. G. Walker, M. Saffman
Physics Faculty Publications
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 μm at the level of 10−3. Ramsey spectroscopy is used to measure a dephasing time of 870 μs, which is ≈5000 times longer than the time for a π/2 pulse.