Infrared Vidicon Camera Research Articles

Mid-infrared supercontinuum generation in telecommunication multimode fiber by nanosecond 2.054 μm laser pulses

We demonstrated a broadband mid-infrared (mid-IR) supercontinuum (SC) directly generated in telecommunication multimode fiber (MMF) pumped by 2.054 μm nanosecond laser pulses. The characteristics of mid-IR SC, including the output spectrum, pulse energy, and optic-to-optic conversion efficiency, were exhaustively investigated at different pump powers and fiber lengths. The nonlinear processes for SC generation in fiber were analyzed, and the frequency shift of the modulation instability (MI) was theoretically calculated, which was close to the experimental data. The output SC pulse shapes were measured in different output powers, and no split was found. The SC laser beam was nearly diffraction limited with an M2 =1.15 in 2.1 μm measured by the traveling knife-edge method, and the laser beam spot was monitored by an infrared vidicon camera.

Half mJ Supercontinuum Generation in a Telecommunication Multimode Fiber by a Q-switched Tm, Ho:YVO4Laser

Up to <TEX>${\sim}520{\mu}J$</TEX> broadband mid-infrared (IR) supercontinuum (SC) generation in telecommunication multimode fiber (MMF) directly pumped by a <TEX>$2.054{\mu}m$</TEX> nanosecond Q-switched Tm, <TEX>$Ho:YVO_4$</TEX> laser is demonstrated. An average output power of 3.64 W is obtained in the band of ~1900 to ~2600 nm, and the corresponding optic-to-optic conversion efficiency is 67% by considering the coupling efficiency. The spectrum has extremely high flatness with negligible intensity variation (<2%) in the wavelength interval of ~2070 to ~2475 nm. The SC long-wavelength edge is limited by the silicon glass material loss, and by optimizing the MMF length, the SC spectrum could extend out to <TEX>${\sim}2.6{\mu}m$</TEX>. The output SC pulse shapes are measured at different output powers, and no splits are found. The SC laser beam is nearly diffraction limited with an <TEX>$M^2=1.15$</TEX> in <TEX>$2.1{\mu}m$</TEX> measured by the traveling knife-edge method, and the laser beam spot is monitored by an infrared vidicon camera.

An All Fiber 1.94 μm Nanosecond Pulse Laser Amplified by Highly Tm3+-Doped Silicon Fibers

We present an all-fiber 1.94 μm nanosecond pulse laser in master oscillation-power amplifier configuration. A dual-FBGs gain-switched Tm3+-doped fiber laser is built and is used as the seed laser. The output characteristics of the amplifier are studied at different pulse repetition rates, and the maximum output energy of 500 μJ is achieved under incident pump power of 39 W. The emitting spectra are checked at 5 and 10 kHz, and no obvious nonlinear effects are observed in the spectrum of the amplified laser. The beam quality factor is M2 = 2.1 ± 0.03 measured by the traveling knife-edge method, and the laser beam spot is also monitored by an infrared vidicon camera.

A single-longitudinal-mode CW 0.25 mm Tm,Ho:GdVO4 Microchip Laser

A single-longitudinal-mode of 0.25 mm Tm,Ho:GdVO4 Microchip Laser was reported. The maximal continuous wave (CW) output power was 26.4 mW and the threshold of 118 mW. The Tm,Ho:GdVO4 Microchip Laser output wavelength was centered at 2039.7598 nm with bandwidth of about 57.1 pm. The beam quality factor was M 2 ∼ 1.52 ± 0.03 measured by knife-edge method. The Longitudinal-Mode was scanned by a FPI and the transverse mode was monitored by an infrared vidicon camera.

Infrared lensless holographic microscope with a vidicon camera for inspection of metallic evaporations on silicon wafers

The lensless digital in-line microscope is proposed as a simple tool for post-production inspection of metallic film patterns on silicon wafers. Transmission holographic imaging is achieved by using a superluminescent diode emitting in the near infrared coupled into a single-mode high numerical aperture optical fiber and an infrared vidicon camera. Images of 300 nm thick vapor-deposited aluminum bolometers are presented.

AlGaAs-based two-dimensional photonic crystal slab with defect waveguides for planar lightwave circuit applications

An AlGaAs-based near-infrared 2-D photonic crystal (PC) with an air-bridge structure featuring defect waveguides has been developed. For the sample without defect waveguides, measurements of the optical transmission characteristics in the wavelength range from 850 nm to 1100 nm showed a deep attenuation due to a bandgap with 30-35 dB attenuation and transmittance of nearly 100% for the guided modes. Optical propagation properties of defect waveguides were obtained by two methods: measurements of transmission spectra and plan-view observations of the optical beam trace along the waveguide with an infrared-vidicon camera. 3-D finite-difference time-domain simulations for the band structure and transmission spectra in the air-bridge slab with and without defect waveguides have revealed the appearance of four defect propagation modes specific to the defect waveguide, between two slab modes for the defect-free photonic crystal slab. These defect modes were experimentally identified in the measured transmission spectra.

Theoretical and experimental investigation of straight defect waveguides in AlGaAs-based air-bridge-type two-dimensional photonic crystal slabs

A detailed investigation was undertaken from both theoretical and experimental perspectives of straight defect waveguides in an AlGaAs-based air-bridge-type two-dimensional photonic crystal slab. Optical propagation properties were obtained by two methods: measurement of transmission spectra at wavelengths ranging from 850 to 1100 nm, and with plan-view observations of the optical beam trace along the waveguide measured with an infrared-vidicon camera. Three-dimensional finite-difference time-domain simulations for the band structure and transmission spectra in the air-bridge slab with and without defect waveguides resulted in the appearance of defect propagation modes specific to the defect waveguide, between two slab modes for the defect-free photonic crystal slab. These defect modes were experimentally identified in the measured transmission spectra.

Usefulness of indocyanine green injection during ultrasound-guided liver biopsy for the diagnosis of small hepatocellular carcinoma.

To diagnose hepatocellular carcinoma (HCC) functionally and immediately, we examined the usefulness of indocyanine green (ICG) injection during ultrasound-guided liver biopsy. Liver specimens were obtained after intravenous ICG injection by ultrasound-guided biopsy from 251 space-occupying lesions (SOL) in 136 patients. The tissues were immediately examined for ICG uptake using an infrared Vidicon camera and were also subjected to histopathological examinations. Of the 112 ICG-negative biopsy specimens, 105 were histologically diagnosed as HCC, 6 as dysplastic nodules (DN) and 1 as a regenerative nodule (RN). Of the 139 ICG-positive specimens, 18 were diagnosed as HCC, 1 as DN and 120 as RN. The sensitivity of the absence of ICG uptake (SEAIU), the specificity of the absence of ICG uptake (SPAIU), and the positive predictive value of the absence of ICG uptake (PPAIU) for the diagnosis of HCC were 85.3%, 94.5% and 93.8%, respectively. Of the 251 SOLs, 184 were less than 2 cm. SEAIU, SPAIU and PPAIU for the diagnosis of these small HCC were 85.3%, 94.5% and 91.4%, respectively. These results support the reliability of ICG injection during ultrasound-guided liver biopsy to diagnose even small HCC.

Some Uses of a Video Cassette Recorder in the Conservation Laboratory

AbstractSeveral uses for a video cassette recorder are presented: in conservation surveys (using a video camera), in conjunction with an infrared vidicon camera, and in the detailed documentation of the surface condition of large works of art.

Optimized PVF 2 targets for infrared vidicon camera tubes

A series of experiments designed to optimize the sensitivity of PVF 2 for use as a target in an infrared camera tube is detailed. It has been found that by thermal pre-stressing and corona poling, sensitivities of 2.5 μA/W are routinely obtainable. Life tests conducted over an 18 month period show no deterioration of sensitivity. Kinescope recordings of images of the human body are presented.