Methods and compositions are provided for detecting biomolecular interactions. The use of labels is not required and the methods can be performed in a high-throughput manner. The invention also provides optical devices useful as narrow band filters.

Label-free high-throughput optical technique for detecting biomolecular interactions

We report on the development of the first widely tunable semiconductor laser with an integrated electroabsorption modulator The laser is a four-section buried-ridge sampled-grating distributed Bragg reflector design It has a 41-nm continuous tuning range with a maximum tuning current of 235 mA for the hack mirror and 21 mA for the front mirror The modulator is based on a 087-eV bandgap bulk waveguide structure It is capable of producing more than 22 dB of optical extinction over the entire tuning range of the laser with a -40-V bias

Widely tunable sampled grating DBR laser with integrated electroabsorption modulator

We report a normal-incident quantum well infrared photodetector (QWIP) strongly coupled with surface plasmon modes. A periodic hole array perforated in gold film was integrated with In0.53Ga0.47As/InP QWIP to convert normal-incident electromagnetic waves into surface plasmon waves, and to excite the intersubband transition of carriers in the quantum wells. The peak responsivity of the photodetector at ∼8 μm was ∼7 A/W at the bias of 0.7 V at 78 K with the peak detectivity as high as ∼7.4×1010 cm Hz1/2/W. The full width at half maximum of the response spectrum was only ∼0.84 μm due to a narrow plasmonic resonance.

http://www.bisol.northwestern.edu/web/papers/ApplPhysLett_96_161107.pdf

Plasmonic enhanced quantum well infrared photodetector with high detectivity

Optical detection of label-free biomolecular interactions using microreplicated plastic sensor elements

Guided mode resonant filter biosensor using a linear grating surface structure

A method for coupling radiation in an infrared detector of the kind which uses quantum wells that are comprised of thin layers of, e.g., gallium arsenide (GaAs) surrounded by aluminum gallium arsenide (AlGaAs). The invention is characterized in that a two-dimensional crossed grating (6), a so-called 2-D grating, is constructed on the top of the detector mesa of the detector on the side opposite the surface through which incident light (5) enters the detector. The grating (6) is caused to spread the incident light in different directions. According to one preferred embodiment, the detector also includes a cladding layer (14) which, together with the crossed grating, forms a wave guide.

Method of coupling radiation in an infrared detector, and an arrangement herefor

In0.53Ga0.47As/InP infrared detectors with peak absorption at a wavelength of 8.5 micrometers have been fabricated and tested. It is shown that very high current responsivities and high gain are obtained. It is found that gain increases drastically when approaching detector voltages close to -8.5 V, which is explained by carrier impact excitation of electrons from the QW ground state to the excited extended state. The detectivity D* is about 1.2(DOT)1010 cm Hz1/2 W-1 at 80 K for a 45 degree(s) polished edge detector assuming unpolarized radiation. Grating coupling is studied by etching crossed gratings into the upper part of the mesas. The increase in responsivity as compared to a polished edge detector is by a factor of 2.5 to 3, irrespective to mesa sizes 500 X 500 or 150 X 150 micrometers 2. This gives a corresponding detectivity of (3 - 3.5)(DOT)1010 cm Hz1/2 W-1 at 80 K for unpolarized radiation.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Long-wavelength quantum-well infrared detectors based on intersubband transitions in InGaAs/InP quantum wells

A wide band reflector, for example a wideband grating reflector is provided as the output coupler of a semiconductor laser. This permits the semiconductor laser to be integrated with other components on a single semiconductor substrate, if desired, without requiring that the laser beam be emitted from the tuning element. Thus, the laser can be tuned over a wide bandwith with efficient power extraction and high wavelength selectivity.

Tunable semiconductor laser with integrated wideband reflector

A method for coupling radiation in an infrared detector of the kind which uses quantum wells that are comprised of thin layers of, e.g., gallium arsenide (GaAs) surrounded by aluminium gallium arsenide (AlGaAs). The invention is characterized in that a two-dimensional crossed grating (6), a so-called 2-D grating, is constructed on the top of the detector mesa of the detector on the side opposite the surface through which incident light (5) enters the detector. The grating (6) is caused to spread the incident light in different directions. According to one preferred embodiment, the detector also includes a cladding layer (14) which, together with the crossed grating, forms a wave guide.

Method of coupling radiation in an infrared detector and device herefor.

An electro-absorption modulator is tunable along with the laser. Tuning the electro-absorption modulator permits optimum detuning to be 5 maintained, even though the laser is tuned over several tens of nm. One approach to tuning the electro-absorption modulator is to heat the electro-absorption modulator. A semiconductor laser device includes a semiconductor laser positioned on a substrate. The semiconductor laser produces output light that is tunable over a tuning range between a first wavelength and a second wavelength. An electro-absorption modulator is disposed to modulate the light produced by the semiconductor laser. The operating temperature of the electro-absorption modulator is tunable so as to maintain constant detuning over at least a portion of the tuning range.

Lennart Lundqvist

Papers

Method of coupling radiation in an infrared detector, and an arrangement herefor

Long-wavelength quantum-well infrared detectors based on intersubband transitions in InGaAs/InP quantum wells

Tunable semiconductor laser with integrated wideband reflector

Method of coupling radiation in an infrared detector and device herefor.

Tunable electro-absorption modulator and tunable laser