Compact high-spectral-radiance fluorescent light source including a parabolic mirror

Abstract

A pumped fluorescent light source includes a parabolic mirror that is positioned to focus pumping light from one or more pump sources on a fluorescent body. The resulting assembly provides for heat collection from a back surface of the light source for both the fluorescent body and the pumping sources in a compact package that may be hermetically sealed. The parabolic mirror has reflective surfaces disposed outside of a collection area of an output beam of the light sources, so that the collection area is not obstructed by the parabolic mirror. The light source also includes a collecting lens for collecting the light emitted by the body. The parabolic mirror focuses the stimulus light on the fluorescent body to stimulate emission. An additional parabolic mirror may be included behind the fluorescent body to focus the fluorescent emissions that do not directly enter the collection area at a point of collection.

Description

BACKGROUND OF THE INVENTION1. Field of the Invention[0001]The present invention is related generally to optical sources, and in particular to a high-radiance fluorescent light source including a parabolic mirror directing stimulus light to a fluorescent body.2. Background of the Invention[0002]In biomedical applications, as well as other applications requiring stimulation of fluorescence or other similar illumination requirements, a broadband optical source is typically needed, as the speckle field generated by narrowband illumination makes narrowband illumination unsuitable for many biomedical and imaging applications, such as optogenetics applications. Historical broadband incoherent light sources require relatively large optical systems and reflectors to concentrate light in a narrow beam in order to provide an efficient source of illumination, and to provide high intensity when coupling into a waveguide such as an optical fiber.[0003]Present-day solid state broadband fluorescent...

AI Technical Summary

Benefits of technology

The patent is about a new light source that is cheaper and smaller than existing sources, but produces high-quality light. The technical effect of this patent is to provide a cost-effective and compact light source with high spectral radiance.

Problems solved by technology

In biomedical applications, as well as other applications requiring stimulation of fluorescence or other similar illumination requirements, a broadband optical source is typically needed, as the speckle field generated by narrowband illumination makes narrowband illumination unsuitable for many biomedical and imaging applications, such as optogenetics applications.

While the use of LEDs as pumps reduces cost and size, the spectral radiance (W / Hz / m2 / sr) of these fluorescent light sources is limited by the radiance (W / m2 / sr) of the pump LED(s) within the absorption band of the fluorescent material, and thermal management of the heat transferred to the fluorescent material from the stimulus.

Such low spectral radiance sources either provide poorly collimated light beams which are not suitable for long-range applications or poorly focused light beams which are not suitable for high-resolution applications and, in particular, for coupling in light guides such as liquid light guides and sub-mm core optical fibers.

First, there are practical space limitations in positioning optical elements in front of the fluorescent body.

Second, when the pump sources are located in front of the fluorescent body, the heat management of the device is complicated by the fact that each pump source generates its own heat load in addition to the pumped fluorescent material.

Finally, the resulting light source requires assembly procedures that raise difficulties in high-volume manufacturing and optical alignment.

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