Differential refractometry by an integrated-optical Young interferometer

被引:47
作者
Brandenburg, A
机构
[1] Fraunhofer-Inst. Phys. Messtechnik, 79110 Freiburg
关键词
differential refractometry; integrated optics; Young interferometers;
D O I
10.1016/S0925-4005(97)80216-X
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
Highly sensitive refractive-index determination is used for process monitoring and quality control, e.g., in the food industry, as a detection principle for HPLC and for applications in research. Because of the large temperature dependence of the refractive index of liquids, sensitivities below 10(-5) are obtained only by differential refractometers. A new detection principle is based on the interference of two divergent rays, produced by an integrated optical splitter. These two rays pass the two flow cells and overlap on a CCD array, producing an interference pattern. The problem of ambiguity of the interference signature is overcome by using partially coherent sources, yielding a modulation of the fringe visibility. The position of fringes on the CCD array is evaluated by Fourier analysis of the intensity distribution. The spacial resolution is about a hundredth of a pixel width, resulting in a refractive-index resolution of 1 X 10(-7) at a measuring range of 5 X 10(-3). The level of signal noise (peak-to-peak) is 3 X 10(-8). Flow-cell volumes are in the range 15-140 mu l. Tests have been performed with regard to process control and HPLC detection, showing the applicability of the system for these different areas.
引用
收藏
页码:266 / 271
页数:6
相关论文
共 12 条
[1]  
Born M., 1986, PRINCIPLES OPTICS
[2]   INTEGRATED OPTICAL YOUNG INTERFEROMETER [J].
BRANDENBURG, A ;
HENNINGER, R .
APPLIED OPTICS, 1994, 33 (25) :5941-5947
[3]  
BRANDENBURG A, 1992, OPTICAL SENSORS
[4]   ELECTRONICALLY SCANNED OPTICAL-FIBER YOUNG WHITE-LIGHT INTERFEROMETER [J].
CHEN, S ;
ROGERS, AJ ;
MEGGITT, BT .
OPTICS LETTERS, 1991, 16 (10) :761-763
[5]   ELECTRONICALLY-SCANNED WHITE-LIGHT INTERFEROMETRY WITH ENHANCED DYNAMIC-RANGE [J].
CHEN, S ;
MEGGITT, BT ;
ROGERS, AJ .
ELECTRONICS LETTERS, 1990, 26 (20) :1663-1665
[6]  
Jackson D. A., 1989, OPTICAL FIBRE SENSOR, P329
[7]  
KERSTEN RT, 1988, OPTICAL FIBER SENSOR, V1, P277
[8]  
KOCH A, 1991, SENSOR ACTUAT A-PHYS, V25, P201
[9]  
Merck KGaA, PRODUCT INFORMATION
[10]   ION-EXCHANGED GLASS WAVE-GUIDES - A REVIEW [J].
RAMASWAMY, RV ;
SRIVASTAVA, R .
JOURNAL OF LIGHTWAVE TECHNOLOGY, 1988, 6 (06) :984-1002