<title>Two applications for microlens arrays: detector fill-factor improvement and laser diode collimation</title>

Abstract

Two of the many applications for microlens arrays are fill factor improvement in focal plane arrays and collimation of laser diode arrays. Most lenslet arrays made for fill factor improvement consist of immersion lenses that themselves do not have a 100% fill and the evaluation of such lenses is not representative of their use in an imaging system. Alternative designs are investigated. Anamorphic optics are required to correct for the astigmatism present in laser diode output. An array of micro-optics with toroidal refractive surfaces can be used to collimate or focus the light. We report on the fabrication and evaluation of such anamorphic micro-optics.

<title>Fill factor improvement using microlens arrays</title>

“…From Eq. (2) and the fact that the microlens f-number is 4, we see that the objective f-number is 10. These values were picked for this example so that a simple design for the objective, a singlet, could be used without introducing significant effects on the point spread function due to aberrations.…”

Review of multiscale optical design

“…In recent designs, the addition of a strongly curved lower microlens functions as a condenser [10,11]. Southwell [12] showed-using physical optics propagation-that if a configuration where an objective lens is focused in the microlens plane and the detector array is positioned at the microlens focal plane, then the resultant MSO optical system achieves increased uniformity of detector illumination and shows decreased sensitivity to variations in incoming light angle.…”

Refractive Micro‐Optics

“…Chirped micro-prism arrays can be used to produce numerous micro-optical elements, including cylindrical and circular lenses [17][18][19]. Such lenses are called micro-Fresnel lenses, and are very often mistakenly referred to as diffractive elements.…”