Reflective thermal lens detection device

Abstract

A reflective thermal lens detection device was developed for realizing a portable and sensitive detector for a microsystem. An aluminum mirror was formed on the main plate of a microchip, and a reflected probe beam was detected with a single pick-up unit. The background signal due to light absorption of the aluminum mirror was 60 times reduced when the microchannel and the mirror were separated with an interval of 600 microm. The tilt angle of the microchip significantly affected the precision of the measurement. Then a quadrant photodiode was used to detect the center of gravity of the reflected probe beam to regulate the tilt angle within +/-0.05 degrees , and this value was enough to achieve 1% CV (coefficient of variance) precision in the measurements. The limit of detection (LOD) was 60 nM for xylene cyanol solution, and the absorbance was 9.4 x 10(-6) AU. About 40 times higher sensitivity was obtained in comparison with a spectrophotometer.

Optofluidic integration for microanalysis

“…While optical telecommunications benefited from needing large numbers of devices providing a few very well defined functions, optical sensing must satisfy many very diverse applications so that the optical phenomenon to be probed and the required sensitivity, specificity, speed and cost may require a different technological solution for each Fig. 21 Illustration of the optical arrangement of a reflective thermal lens detection device (Mawatari and Shimoide 2006). Reproduced with permission from the Royal Society of Chemistry application (Culshaw 2004).…”

“…This was achieved by forming an aluminium mirror on the reverse of the microchip. The reflected probe beam was detected with 40 times higher sensitivity when compared to a spectrophotometer, with an LoD of 60 nM for xylene cyanol solution (Mawatari and Shimoide 2006). Ghaleb and Georges have reviewed and analysed the use of crossed-beam systems, in which the excitation beam and probe beam are perpendicular to each other, in comparison with the collinear approach normally used in TLM.…”

Progress in Thermal Lens Spectrometry and Its Applications in Microscale Analytical Devices

“…Focusing resolutions for depth and width directions were 1 and 10 mm, respectively. The same authors then developed a reflective portable TLM (Mawatari and Shimoide, 2006). An aluminum mirror was deposited on the main plate of the microchip to reflect the probe beam back to a detection unit.…”

Design of an Angle Detector for Laser Beams Based on Grating Coupling

“…Precise tracking of laser beams has innumerable applications, including but not limited to lidar, chemical/biochemical microsystems, microscopy, optical tweezers, telescopes, satellite communications, and optical interconnects [1,2]. Among these applications, in recent years optical…”