A simple technique for measureing the M2 parameter, optical focus, astigmatism and ellipticity of the light exiting an objective lens in a laser scanning microscope

Greg Norris, Stuart Wilson, Johanna Trägårdh, Christopher Travis, Gian-Luca Oppo, Gail McConnell

Research output: Contribution to conferencePoster

Abstract

We report a method for measuring the optical quality of the post-objective laser radiation in a laser scanning microscope. We use a microscopic-scale knife-edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide and a light-collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, an error function measuring the beam can be obtained and by repeating this with the knife-edge at different axial positions relative to the beam waist, the M2 parameter of the post-objective laser beam can be obtained, together with measurements of the size of the optical focus, the ellipticity and the astigmatism of the laser beam exiting the objective lens. This measurement is useful not only for measuring the size of the optical focus, but also for evaluating the beam divergence and thus evaluating how much of the full numerical aperture of the lens is used in practice, which impacts the image quality in confocal and multi-photon microscopy
LanguageEnglish
PagesP1-C/04
Publication statusPublished - Apr 2014
EventFocus on Microscopy, FOM 2014 - Sydney, Australia
Duration: 13 Apr 201416 Apr 2014

Conference

ConferenceFocus on Microscopy, FOM 2014
CountryAustralia
CitySydney
Period13/04/1416/04/14

Fingerprint

Astigmatism
astigmatism
ellipticity
Lenses
Lasers
microscopes
lenses
Light
scanning
lasers
laser beams
grids
Optical Fibers
error functions
numerical aperture
Transmission Electron Microscopy
Photons
chutes
photodiodes
Glass

Keywords

  • beam measurement
  • M-squared
  • ellipticity
  • multi-photon

Cite this

@conference{dafe2ef0b79740a5975de8b89a8fbd12,
title = "A simple technique for measureing the M2 parameter, optical focus, astigmatism and ellipticity of the light exiting an objective lens in a laser scanning microscope",
abstract = "We report a method for measuring the optical quality of the post-objective laser radiation in a laser scanning microscope. We use a microscopic-scale knife-edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide and a light-collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, an error function measuring the beam can be obtained and by repeating this with the knife-edge at different axial positions relative to the beam waist, the M2 parameter of the post-objective laser beam can be obtained, together with measurements of the size of the optical focus, the ellipticity and the astigmatism of the laser beam exiting the objective lens. This measurement is useful not only for measuring the size of the optical focus, but also for evaluating the beam divergence and thus evaluating how much of the full numerical aperture of the lens is used in practice, which impacts the image quality in confocal and multi-photon microscopy",
keywords = "beam measurement, M-squared, ellipticity, multi-photon",
author = "Greg Norris and Stuart Wilson and Johanna Tr{\"a}g{\aa}rdh and Christopher Travis and Gian-Luca Oppo and Gail McConnell",
year = "2014",
month = "4",
language = "English",
pages = "P1--C/04",
note = "Focus on Microscopy, FOM 2014 ; Conference date: 13-04-2014 Through 16-04-2014",

}

A simple technique for measureing the M2 parameter, optical focus, astigmatism and ellipticity of the light exiting an objective lens in a laser scanning microscope. / Norris, Greg; Wilson, Stuart; Trägårdh, Johanna; Travis, Christopher; Oppo, Gian-Luca; McConnell, Gail.

2014. P1-C/04 Poster session presented at Focus on Microscopy, FOM 2014, Sydney, Australia.

Research output: Contribution to conferencePoster

TY - CONF

T1 - A simple technique for measureing the M2 parameter, optical focus, astigmatism and ellipticity of the light exiting an objective lens in a laser scanning microscope

AU - Norris, Greg

AU - Wilson, Stuart

AU - Trägårdh, Johanna

AU - Travis, Christopher

AU - Oppo, Gian-Luca

AU - McConnell, Gail

PY - 2014/4

Y1 - 2014/4

N2 - We report a method for measuring the optical quality of the post-objective laser radiation in a laser scanning microscope. We use a microscopic-scale knife-edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide and a light-collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, an error function measuring the beam can be obtained and by repeating this with the knife-edge at different axial positions relative to the beam waist, the M2 parameter of the post-objective laser beam can be obtained, together with measurements of the size of the optical focus, the ellipticity and the astigmatism of the laser beam exiting the objective lens. This measurement is useful not only for measuring the size of the optical focus, but also for evaluating the beam divergence and thus evaluating how much of the full numerical aperture of the lens is used in practice, which impacts the image quality in confocal and multi-photon microscopy

AB - We report a method for measuring the optical quality of the post-objective laser radiation in a laser scanning microscope. We use a microscopic-scale knife-edge in the form of a simple transmission electron microscopy grid attached to a glass microscope slide and a light-collecting optical fibre and photodiode underneath the specimen. By scanning the laser spot from a reflective to a transmitting part of the grid, an error function measuring the beam can be obtained and by repeating this with the knife-edge at different axial positions relative to the beam waist, the M2 parameter of the post-objective laser beam can be obtained, together with measurements of the size of the optical focus, the ellipticity and the astigmatism of the laser beam exiting the objective lens. This measurement is useful not only for measuring the size of the optical focus, but also for evaluating the beam divergence and thus evaluating how much of the full numerical aperture of the lens is used in practice, which impacts the image quality in confocal and multi-photon microscopy

KW - beam measurement

KW - M-squared

KW - ellipticity

KW - multi-photon

UR - http://www.focusonmicroscopy.org/2014/index.html

M3 - Poster

SP - P1-C/04

ER -