Focusing of spherical Gaussian beams

Self, S. A.

doi:10.1364/ao.22.000658

Cited by 307 publications

(130 citation statements)

References 2 publications

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“…2a, we show the profile of the Gaussian beam at the output of the telescope characterized with a beam profiler. We obtained a minimum Gaussian beam waist of 4.82 ± 0.04 µm, which was close to the 4.8 µm waist that we obtained from theoretical calculations [13].…”

Section: Optical Systemsupporting

confidence: 88%

Free-space-coupled superconducting nanowire single-photon detectors for infrared optical communications

et al. 2016

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This paper describes the construction of a cryostat and an optical system with a free-space coupling efficiency of 56.5% ± 3.4% to a superconducting nanowire single-photon detector (SNSPD) for infrared quantum communication and spectrum analysis. A 1K pot decreases the base temperature to T = 1.7 K from the 2.9 K reached by the cold head cooled by a pulse-tube cryocooler. The minimum spot size coupled to the detector chip was 6.6 ± 0.11 µm starting from a fiber source at wavelength, λ = 1.55 µm. We demonstrated efficient photon counting on a detector with an 8 × 7.3 µm 2 area. We measured a dark count rate of 95 ± 3.35 kcps and a system detection efficiency of 1.64% ± 0.13%. We explain the key steps that are required to further improve the coupling efficiency.

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Section: Optical Systemsupporting

confidence: 88%

Free-space-coupled superconducting nanowire single-photon detectors for infrared optical communications

et al. 2016

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“…However, this distribution also requires a correction [p 2 o 0 4 /l 2 (aÀf)] (o 0 is the characteristic Gaussian-mode beam radius) to the distance a in the lens equation. 15 In our case this addition is negligible owing to the small value of the single-mode core radius. Third, the influence of the aberration effects on the CFOLM measurement accuracy is negligible because a monochromatic laser emission is used, the mirror displacement is along the axis with additional angular adjustment, and the laser beam distribution is Gaussian with strongly decreasing intensity in the laser spot periphery.…”

Section: Resultsmentioning

confidence: 69%

A simple confocal fibre-optic laser method for intraocular lens power measurement

Ilev

2006

Eye

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IK Ilev AbstractPurpose To develop novel confocal fibreoptic laser method (CFOLM) for accurate and objective measuring of the dioptric power of both positive and negative intraocular lenses (IOLs). Methods The CFOLM principle of operation is based on a simple apertureless single-mode fibre laser confocal design. The key element is a single-mode fibre coupler that serves simultaneously as a point light source (3-5 lm fibre diameter) used for the formation of a collimated Gaussian beam, and as a confocal point receiver that is highly sensitive to spatial displacements of the focused backreflectance laser emission. The basic CFOLM systems include IOL testing set-ups for the measurement of both positive and negative IOLs. Results The CFOLM designs provide high accuracy (r1 lm) in spatially locating the IOL focal point and in measuring the focal length in a broad range of both positive and negative powers including high-magnification IOLs with power greater than 720 D. We have tested various IOL samples with both positive ( þ 5 to þ 30 D) and negative (À5 to À20 D) powers and we have obtained high levels of power testing repeatability estimated by a SD in the interval of 0.004-0.06/0.003-0.013 D and a relative error in the interval of 0.015-0.3/0.02-0.16%, for positive/negative IOLs, respectively. Conclusions The presented IOL power testing method offers a simple, accurate, objective, quick, and relatively inexpensive approach for dioptric power measurement of positive and negative IOLs. It provides an independent source of IOL power measurement data and information for evaluating the effectiveness and safety of novel IOL products.

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“…The adjustable iris (SM1D12 from ThorLabs, Inc.) diameter was set at ∅6.5mm, yielding f/# = 23.08. The beam spot of a diffraction-limited lens can be calculated using [36]:…”

Section: Methodsmentioning

confidence: 99%

Thin laser light sheet microscope for microbial oceanography

Fuchs¹,

Jaffe²,

Long³

et al. 2002

Opt. Express

161

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Despite a growing need, oceanographers are limited by existing technological constrains and are unable to observe aquatic microbes in their natural setting. In order to provide a simple and easy to implement solution for such studies, a new Thin Light Sheet Microscope (TLSM) has been developed. The TLSM utilizes a well-defined sheet of laser light, which has a narrow (23 micron) axial dimension over a 1 mm x 1 mm field of view. This light sheet is positioned precisely within the depth of field of the microscope's objective lens. The technique thus utilizes conventional microscope optics but replaces the illumination system. The advantages of the TLSM are two-fold: First, it concentrates light only where excitation is needed, thus maximizing the efficiency of the illumination source. Secondly, the TLSM maximizes image sharpness while at the same time minimizing the level of background noise. Particles that are not located within the objective's depth of field are not illuminated and therefore do not contribute to an out-of-focus image. Images from a prototype system that used SYBR Green I fluorescence stain in order to localize single bacteria are reported. The bacteria were in a relatively large and undisturbed volume of 4ml, which contained natural seawater. The TLSM can be used for fresh water studies of bacteria with no modification. The microscope permits the observation of interactions at the microscale and has potential to yield insights into how microbes structure pelagic ecosystems.

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Focusing of spherical Gaussian beams

Abstract: Simple procedures and formulas for tracing the characteristics of a spherical Gaussian beam through a train of lenses or mirrors are described which are analogous to those used in geometrical optics to trace repeated images through an optical train.

Cited by 307 publications

References 2 publications

Free-space-coupled superconducting nanowire single-photon detectors for infrared optical communications

Free-space-coupled superconducting nanowire single-photon detectors for infrared optical communications

A simple confocal fibre-optic laser method for intraocular lens power measurement

Thin laser light sheet microscope for microbial oceanography

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