Multichannel raman scattering: Comparison of an intensified linear diode array and an ICCD detector

A comparison of the Signal to Noise (S/N) ratio was made between an Intensified Linear Diode Array detector (ILDA) and an Intensified Charge Coupled Device (ICCD) applied to single shot pulsed spontaneous Raman spectroscopy with an excimer laser. As a result in this special application the S/N ratio of an ILDA is two times better than that of an ICCD.     

Multichannel polarization interferometers

Measurement Techniques -     

Multichannel instrument amplifier

Summary The design of multichannel devices with a common intermediate amplifier provides a reduced measurement error and a considerable reduction in the amplifying elements, which in turn raises the reliability of the device and reduces its size and weight.     

多波段水下光谱辐射计

研制了基于干涉滤光片分光的船载多波段水下光谱辐射计，该辐射计可同步观测12波段下行光谱辐照度、12波段上行光谱辐照度和7波段上行光谱辐亮度，水下剖面测量深度达200m。在水槽中测定了辐照度探头的余弦响应特性和浸没因子，利用MonteCarlo方法模拟了阴影误差分布，给出了仪器的主要性能指标。给出了与Macam公司SR9910c型水下光谱仪的比对结果以及海上试验数据的分析结果。     

Multichannel quartz crystal microbalance

Arrays of quartz crystal resonators are fabricated on a single quartz wafer as a multichannel quartz crystal microbalance (MQCM). Three types of four-channel array of 10-MHz resonators are prepared and tested. Mechanical oscillation of each channel is entrapped within the channel almost completely, so that the interference between the channels via the quartz crystal plate is almost negligible. A mass change on each channel is quantitatively evaluated on the basis of Sauerbrey's law. Thus, each channel of a MQCM device can be used as an independent QCM. Influence from a longitudinal wave generated from another channel is also negligible compared to the influence from the wave from the monitored channel itself. The simultaneous oscillation of channels is also possible. The potential applicability of MQCM to the two-dimensional mapping of mass changes is demonstrated.     

Multichannel mode-filtered light detection based on an optical fiber for small-volume chemical analysis

A novel mode-filtered light detection method is described in which an unjacketed optical fiber is inserted into a transparent capillary tube and three or more detection channels are set on the capillary side for different distances from the port of the fiber. This new method is the basis of synchronization of separation and analysis, with which a modern multidimensional analysis apparatus will be constructed. For samples of different concentration, the more close to the laser incidence port of the fiber the detector has been set up, the greater the change of the intensity profile of mode-filtered light (deltaI(F)) that is obtained. Vice versa, if a parameter alpha = I0/In is established and, instead of a mode-filtered light signal, the reversed alteration trend of deltaalpha is found in comparison with the alteration trend of deltaI(F), the reason is that the background rapidly lowers with the increasing distance to the laser incidence port of the fiber; moreover, the mode-filtered light signal decreases slowly with it. With the present method and apparatus, glucose and glycerol have been determined, with good reproducibility and stability and a small sample volume. Furthermore, a real sample of glucose injection is measured for a detection volume of 5 microL, and an acceptable result is observed.