Performance of a diaphragmed microlens for a packaged microspectrometer

Area of Science:

• Optics and Photonics
• Micro-electro-mechanical Systems (MEMS)
• Spectroscopy

Background:

• Microspectrometers require precise optical components for accurate spectral analysis.
• Integrating microlenses into MEMS devices presents fabrication and performance challenges.

Purpose of the Study:

• To design, fabricate, package, and test a microlens integrated into a MEMS microspectrometer.
• To develop and apply methods for characterizing micro-optic parameters crucial for spectroscopic applications.

Main Methods:

• Fabrication of a suspended microlens diaphragm using modified polydimethylsiloxane (PDMS) molding.
• Utilizing a Gaussian beam propagation model to determine focal length and M(2) value.
• Employing a tunable calibration source and CCD imaging for device response and spectral output analysis.

Main Results:

• Successful fabrication and integration of a PDMS microlens within a multi-layered MEMS microspectrometer.
• Quantification of microlens optical parameters, including focal length and beam quality (M(2) value).
• Demonstration of dual wavelength separation using the packaged microspectrometer, verified by CCD imaging and beam profiling.

Conclusions:

• The developed microlens and characterization techniques are vital for optimizing MEMS-based spectroscopic devices.
• This work provides a framework for measuring critical parameters in micro-optic systems.
• The integrated microlens shows promise for enhancing the performance of miniaturized spectrometers.