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We have demonstrated efficient speckle reduction techniques by using both overlapping and mixing techniques. A phosphor sample is used for white light generation. The speckle contrast (SC) can be reduced from 38.5% to 7.8% for a MEMS scanning blue LD area. The speckle-free results are achieved for mixed white light source.

We have demonstrated efficient speckle reduction techniques by using both micro-vibrated and mixing light methods for solid-state backlighting source applications. A micro-vibrated-reflectivephosphor paper is used for speckle suppression and white light generation. A mixing speckle contrast (SC) is defined, and the almost speckle-free results are achieved.

In this paper, we have demonstrated an efficient speckle-suppressed white light source generation when a blue laser diode illuminates on a micro-vibrated phosphor paper. Both micro-vibrated and color-mixing techniques are used in this system. With only micro-vibrated technique, the speckle contrast can be reduced from about 50% to 7.4% for the scattering blue image for a 16-ms integration time. Together with color-mixing technique, mixing speckle contrast is defined for laser diode pumped phosphor and almost speckle-free result is achieved. For color temperature lower than 5000 K, almost speckle-free mixed white can be obtained even without vibration technique.

We have demonstrated the use of laser scanning confocal microscope for mapping the refractive index as well as Cr 3+ and Cr 4+ fluorescence in Cr:YAG crystal fibers with 1 μm spatial resolution. The corresponding sensitivities for Cr 3+ and Cr 4+ fluorescence intensities are 1.6×10 17 /cm 3 and 7.5×10 15 /cm 3 , respectively. The share of Cr 4+ ions in the total Cr concentration is found to be proportional to the ratio of Ca to Cr concentrations. However, only less than 1% of the Ca 2+ ions become active in charge compensation. The concentration of Cr 4+ ions is higher near the center of the crystal fiber when the core diameter is less than 300 μm. In addition, stress-induced striations created near the fiber center disappear when the fiber diameter is smaller than 500 μm.

We have demonstrated an efficient speckle reduction method for laser illumination using a micro-vibrated paper screen along the projection direction. Using this method, a micro-vibrated amplitude of 0.532 μm, or a 2π phase change is sufficient to de-correlate the generated speckle pattern for a static SHG green laser beam image. When the measured speckle contrast is lowered to about 5.0%, and comparable with an LED source, a speckle-free image can be achieved. This technique will be suitable for compact and portable laser illumination equipment, image display, signal sensing devices, and so forth. Wearable and near-to-eye laser display applications are also included.

The extremely small angle speckle-suppressed partial random laser illuminating system with ~0.1deg. divergence angle is realized. The speckle contrast of 8.5% in a 16 ms is reached. A 0.55 mW CW partial random laser is achieved.

A compact tunable UV laser source based on intracavity sum frequency generation in a MgO-doped periodically-poled stoichiometric lithium tantalate optical parametric oscillator is reported. UV output at an approximately 1 mW level of power over the range of 364 to 378 nm with a bandwidth of 0.5 nm was obtained with a crystal that has just one periodically-poled grating period. The full tuning range can be as much as approximately 68 nm, from 324 to 392 nm by varying the crystal temperature from room temperature to 250 degrees C. This will cover nearly the entire UVA range.

1.611 0.011, 1.683 0.013, 1.688 0.010, and 0.016 0.005, respectively. Our values are in excellent agreement with theoretical prediction. The spectral line shapes of autoionizing Rydberg states are analyzed with a Beutler-Fano profile. Reduced autoionization linewidths for the np1 / 20n =1 1–1 6 series vary in the range 2549– 4145 cm �1 , and the nf5 / 22n =9–1 1 series in 186– 247 cm �1 in reasonable agreement with theoret

A compact pulsed RGB laser source based on periodically-poled MgO doped SLT pumped at 532 nm is reported. The operation of the source at near-room temperature and at high temperature is evaluated for optimal performance.

A compact multi-kHz UV source tunable from 363 nm to 378 nm is realized by intracavity SFG in a PPMgSLT OPO. Phase-matched peaks at 334 nm and 370 nm are observed. A full tuning range of ~58 nm is predicted.

We report the first pulsed high average power visible optical parametric oscillator based on periodically-poled LiTaO3. Stable operation indicates that the 370 mW visible output obtained should be scalable to much higher power.

An efficient 532 nm-pumped pulsed OPO that could be operated at room temperature using a PPMgSLT crystal is reported. >1.0 W total output for a 1.6 W input (power conversion of 62.5%) was achieved.

A pulsed tunable optical parametric oscillator using periodically-poled stoichiometric lithium tantalate pumped at 532 nm is reported. The tuning range achieved was from 0.65 /spl mu/m to 2.97 /spl mu/m and the photon conversion efficiency was 40%.

Two pulsed grazing-incidence PPLN OPO's are used to generate mid-IR radiation by difference mixing in zinc germanium phosphide. 22% photon conversion was achieved with 87 mW average input power.

A low-propagation-loss (< 0.1 dB/cm) fused-silica-clad Cr:YAG fiber is demonstrated and investigated. The simulation shows that more than 0 dBm of amplified spontaneous emission could be generated with a 2-W pump and an 8-/spl mu/m core.

Glass-clad Cr4+:YAG crystal fiber is demonstrated by a codrawing laser-heated pedestal growth method. As much as 2.45 mW of superwideband amplified spontaneous emission (ASE) is generated in the optical fiber communication band with a 3-dB width of 240 nm. The simulation indicates that the ASE power could be in excess of 20 dBm for a 5-microm-diameter core at a pump power of 2.5 W.

A high-power 532 nm-pumped multikilohertz nanosecond optical parametric oscillator using a periodically poled 1.0 mol.% MgO-doped stoichiometric lithium tantalate crystal that could be operated from room temperature to 200 degrees C without damage is reported. A broad continuous tuning range from 855 to 1410 nm was achieved within a single domain period. Efficient operation of high peak power and watt level average power with a power conversion of 62.5% was measured. These results show that a high-resolution high average power visible tunable source can be realized.

A compact, pulsed, red, green, and blue laser source based on cascaded quasi-phase-matched wavelength conversion in two periodic superlattices set in tandem in a single stoichiometric LiTaO3 crystal and pumped by a laser source at 532nm is reported. The white light equivalent flux obtained was 80lmper1W input with a green to white light power conversion efficiency of >30%. Unity power conversion is feasible in this monolithic approach.

Detachment of heme prosthetic groups from gaseous myoglobin ions has been studied by collision-induced dissociation and infrared multiphoton dissociation in combination with Fourier-transform ion cyclotron resonance mass spectrometry. Multiply charged holomyoglobin ions (hMbn+) were generated by electrospray ionization and transferred to an ion cyclotron resonance cell, where the ions of interest were isolated and fragmented by either collision with Ar atoms or irradiation with 3 mum photons, producing apomyoglobin ions (aMbn+). Both charged heme loss (with [Fe(III)-heme]+ and aMb(n-1)+ as the products) and neutral heme loss (with [Fe(II)-heme] and aMbn+ as the products) were detected concurrently for hMbn+ produced from a myoglobin solution pretreated with reducing reagents. By reference to Ea = 0.9 eV determined by blackbody infrared radiative dissociation for charged heme loss of ferric hMbn+, an activation energy of 1.1 eV was deduced for neutral heme loss of ferrous hMbn+ with n = 9 and 10.

A compact, efficient optical parametric oscillator (OPO) for the visible to near-infrared region based on periodically poled stoichiometric lithium tantalate pumped by a frequency-doubled multikilohertz Q-switched Nd:YAG laser is demonstrated. Up to 61% photon conversion with a 71% slope efficiency for photon conversion from 532 nm to the signal radiation was measured. We observed that the efficient conversion diminished the potential for photorefractive damage induced by the 532 nm radiation in the crystal and made sustained operation of the OPO device possible.

A novel technique, using cascaded first-order second harmonic generation and third-order sum frequency generation in a ZnO:PPLN crystal fiber, was demonstrated for the generation of tunable blue/green laser from 471.3 nm to 515 nm.