Carrier-Induced Index Change in AlGaAs and InGaAsP Lasers and Its Influence on Optical Waveguiding

AbstractQuantification of molecular interactions on a surface is typically achieved via label-free techniques such as surface plasmon resonance (SPR). The sensitivity of SPR originates from the characteristic that the SPR angle is sensitive to the surface refractive index change. Analogously, in another interfacial optical phenomenon, total internal reflection, the critical angle is also refractive index dependent. Therefore, surface refractive index change can also be quantified by measuring the reflectivity near the critical angle. Based on this concept, we develop a method called critical angle reflection (CAR) imaging to quantify molecular interactions on glass surface. CAR imaging can be performed on SPR imaging setups. Through a side-by-side comparison, we show that CAR is capable of most molecular interaction measurements that SPR performs, including proteins, nucleic acids and cell-based detections. In addition, we show that CAR can detect small molecule bindings and intracellular signals beyond SPR sensing range. CAR exhibits several distinct characteristics, including tunable sensitivity and dynamic range, deeper vertical sensing range, fluorescence compatibility, broader wavelength and polarization of light selection, and glass surface chemistry. We anticipate CAR can expand SPR′s capability in small molecule detection, whole cell-based detection, simultaneous fluorescence imaging, and broader conjugation chemistry.

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Optical properties of benzene and derivatives by the single beam thermal lens technique

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s0218863517500254 ◽

2017 ◽

Vol 26 (02) ◽

pp. 1750025 ◽

Cited By ~ 1

Author(s):

M. K. Biswas ◽

P. K. Das ◽

E. Hoque ◽

S. M. Sharafuddin ◽

S. K. Das ◽

...

Keyword(s):

Thermal Lens ◽

Continuous Wave ◽

Refractive Index Change ◽

Optical Nonlinearity ◽

Index Change ◽

Single Beam ◽

Cw Laser ◽

Ion Laser ◽

Benzene Toluene ◽

Long Pulse

The present work studies the optical nonlinearity exhibited by the material (for Continuous Wave (CW) laser or long pulse) due to the change in thermal properties of the material on illumination. Thermal lens (TL) technique has been used to measure the refractive index change due to the formation of TL along with other thermo-optic properties of the material in solution. A CW Ar-ion laser has been used as light source and the laser beam was chopped at 25[Formula: see text]Hz frequency to obtain 12[Formula: see text]ms pulse to observe the formation of the TL within the sample. The [Formula: see text] value have been calculated by the TL technique for Benzene, Toluene and Dimethylaniline (DMA) in toluene and Benzene. The [Formula: see text] value is found to be in the order of 10[Formula: see text] to 10[Formula: see text][Formula: see text]cm2[Formula: see text]W[Formula: see text].

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