Laser diode sensor
First Claim
1. A surface-active laser chemical sensor for detecting chemical changes in an ambient environment comprising a substrate, a diode laser structure deposited on the substrate for generating a laser signal, the laser structure further comprising an active layer, a barrier layer on the active layer, a cladding layer on the barrier layer, and a reducing layer on the cladding layer, a contact layer formed on the reducing layer having a deposited electrode, a surface sensitive region adjacent to the electrode, wherein in the surface sensitive region the thickness of the cladding layer is from 0.5 microns to less than 0.05 microns to enable a tail of a lasing mode to have a finite value at the surface of the laser, such that the laser structure and the signal generated by the laser structure exhibit sensitivity to an analyte at the surface sensitive region, wherein the laser structure produces in the presence of the analyte a laser signal, and wherein the laser signal is detected by a detector.
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Accused Products
Abstract
A chemical sensor uses a semiconductor diode laser having a surface active region. A laser structure, including an active layer, a cladding layer, a barrier layer and a grating layer, is constructed on a substrate. A contact layer is deposited on a surface of the laser structure. One or more electrodes are positioned on the contact layer. A segmented electrode has a first contact pad, a second contact pad, and a surface active region between the first and second pads. A surface active region is created between the two electrodes. The tail of the lasing signal interacts with surface features of the diode laser or with chemical materials or probes in contact with the surface of the diode laser or in contact with coatings on the surface of the diode laser. Chemical changes in the ambient environment induce changes in the laser signal. The modified laser signal output is detected by a detector region integral with or separated from the laser structure. The laser diode sensor has applications in fields involving chemical sensing and identification, including automotive, environmental and medical fields.
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Citations
33 Claims
- 1. A surface-active laser chemical sensor for detecting chemical changes in an ambient environment comprising a substrate, a diode laser structure deposited on the substrate for generating a laser signal, the laser structure further comprising an active layer, a barrier layer on the active layer, a cladding layer on the barrier layer, and a reducing layer on the cladding layer, a contact layer formed on the reducing layer having a deposited electrode, a surface sensitive region adjacent to the electrode, wherein in the surface sensitive region the thickness of the cladding layer is from 0.5 microns to less than 0.05 microns to enable a tail of a lasing mode to have a finite value at the surface of the laser, such that the laser structure and the signal generated by the laser structure exhibit sensitivity to an analyte at the surface sensitive region, wherein the laser structure produces in the presence of the analyte a laser signal, and wherein the laser signal is detected by a detector.
Specification