Measurement of Gaussian laser beam radius using the knife-edge technique: improvement on data analysis

Abstract

We revisited the well known Khosrofian and Garetz inversion algorithm [Appl. Opt.22, 3406-3410 (1983)] that was developed to analyze data obtained by the application of the traveling knife-edge technique. We have analyzed the approximated fitting function that was used for adjusting their experimental data and have found that it is not optimized to work with a full range of the experimentally-measured data. We have numerically calculated a new set of coefficients, which makes the approximated function suitable for a full experimental range, considerably improving the accuracy of the measurement of a radius of a focused Gaussian laser beam.

Irreversible modification of magnetic properties of Pt/Co/Pt ultrathin films by femtosecond laser pulses

“…Laser pulses of wavelength of 800 nm, duration of 60 fs, and energy in the range of 1.3-4.6 lJ (measured carefully with a power meter working in a single pulse mode) were focused at the sample surface with a lens. Determining the beam radius with the knife-edge method 19,20 showed that the spatial profile of the beam used in our experiment is fitted well with a sum of two Gaussian profiles. 21 The radii of both Gaussian components were equal to: r 1 ¼ (33.8 6 0.5)lm, r 2 ¼ (217 6 21)lm, with a dominant contribution of (98.6 6 0.4)% of the first one.…”

Sistema fotodetector econômico para utilização em laboratórios de ensino e pesquisa

“…Nesse trabalho, a determinação da largura do feixe foi feita num ponto indeterminado ao longo do eixo de propagação. A medida da largura do feixe pode ser feita por meio do método da lâmina [9,10], o qual consiste na quantificação da luz que atinge o detector como função da posição de uma lâmina queé deslocada perpendicularmenteà direção de propagação do feixe, por meio de um parafuso micrométrico. Para uma medida precisa, após a lâminaé posicionada uma lente a qual focaliza o feixe sobre o fotodetector.…”

Rapid spontaneous Raman light sheet microscopy using cw-lasers and tunable filters

“…the integral) of the beam is traced. Since the resulting trace does not replicate by itself the beam profile, a proper data inversion method needs to be used to finally obtain the beam intensity profile [19][20][21]. Figures 1(a) …”