Work

Determination of the contributions of two simultaneous absorption orders using 2-beam action spectroscopy

Year: 2018

Type: article

Abstract: The concept of a 2-beam action (2-BA) spectroscopy was recently introduced as a method for determining the order of effective nonlinear absorption in multiphoton photoresists. Here we demonstrate that the 2-BA approach can be extended to any measureable observable generated by linear and/or nonlinear absorption. As an example, 2-beam constant-amplitude photocurrent spectroscopy is used to study absorption of a tightly focused, mode-locked or continuous-wave, 800 nm laser by a GaAsP photodiode. The effective order of the absorption process can be measured at any desired value of the photocurrent or photovoltage. A self-consistent framework is presented for using non-integral 2-BA exponents to determine the relative contributions of two absorption mechanisms of different order. The dependence of the ratio of the quadratic and linear contributions on the average excitation power is used to verify that these are the dominant orders of absorption in the photodiode with 800 nm excitation.

Source: Optics Express

DOI: 10.1364/oe.26.009492

Authors: Nikolaos Liaros, Samuel R. Cohen, John T. Fourkas

Institution: University of Maryland, College Park

Language: English

Topic: Nonlinear Optical Materials Studies

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,270

Funder: National Science Foundation