RESUMEN

Linear arrays of thin membrane (0.5-0.8-microm) pyroelectric PVF(2) detectors have been constructed. The size of each element was 0.1 x 3 mm. The arrays were built with twenty-four channels of hybrid self-scanning electronics and packaged in vacuum containers, D* of 1.5 x 10(9) cm/Hz/W at 10 Hz and thermal cross talk of <15% at 50 Hz were obtained.

RESUMEN

In certain biological and medical applications it is important to measure and follow temperature changes inside a body or tissue. Any probe inserted into a tissue causes damage to tissue and distortion to the initial temperature distribution. To minimize this interference, a fine probe is needed. Thus, thin film technology is advantageous and was utilized by us to produce sensitive probes for these applications. The resulting probe is a small thermocouple at the tip of a thin needle (acupuncture stainless steel needle, approximately 0.26 mm in diameter and length in the range 5-10 cm was used). The junction was produced at the needle's tip by coating the needle with thin layers of insulating and thermoelectric materials. The first layer is an insulating one and is composed of polyacrylonitrile (PAN) and polymide produced by plasma polymerization and dip-coating respectively. This layer covers all the needle except the tip. The second layer is a vacuum deposited thermoelectric thin layer of Bi-5% Sb alloy coating also the tip. The third layer is for insulation and protection and is composed of PAN and polyimide. In this arrangement the junction is at the needle's tip, the needle is one conductor, the thermoelectric layer is the other and they are isolated by the plastic layer. The probe is handy and mechanically sturdy. The sensitivity is typically 77 microV/degrees C at room temperature and is constant to within 2% up to 90 degrees C. The response is fast (less than 1 sec) the noise is small, (less than 0.05 degrees C) and because of the small dimension, damage to tissue and disturbance to the measured temperature field are minimal.

Asunto(s)

Acrilonitrilo , Agujas , Nitrilos , Termómetros , Resinas Acrílicas , Ciclohexanos , Conductividad Eléctrica , Polímeros , Semiconductores , Acero Inoxidable , Temperatura , Conductividad Térmica

RESUMEN

Membranes as thin as 500 A were produced from many plastic materials and transferred to frames with dimensions of several centimeters. The self-supporting membranes were obtained using simple-dip-coating techniques. In some cases additional plasma polymerized layers were applied. These membranes can withstand several procedures of photolithography and chemical processing. The mechanical properties of the membranes are similar to that of the bulk material. Some typical applications are described. These applications include the use of the membranes as substrates for thermoelectric detectors and also as beamsplitters and windows for cells employed in CO(2) laser spectroscopy.

RESUMEN

A novel photodielectric polymer system suitable for recording high resolution volume phase holograms is described. Highly reactive monomers that polymerize rapidly when inserted between two substrates allow for simple and convenient preparation of recording layers ranging from 10microm to 3 mm. The materials have superior chemical and dimensional stability and have in situ self-developing capabilities. During recording the polymer cross-links in the irradiated regions causing changes in index of refraction. Experimental measurements reveal that the diffraction efficiencies may exceed 90%, that the resolution is in excess of 2000 lines/mm, that the angular selectivity may be as high as several minutes of arc, and that the noise characteristics are comparable to those of high quality photographic emulsions. The hologram formation mechanism along with experimental results of exposure sensitivities, diffraction efficiencies, SNRs, and angular discrimination are presented.