Optical MEMS

Single-Axis Micromirror

MEMS micromirror  is a key element of many optical system. Mirror performance is measured thanks to the unique 3D time-sequence topography the DHM characterization allows :

  • Surface topography : surface finish, flatness
  • Dynamic properties : modal frequency, mode shapes

Efficient characterization of mode shapes

Micromirror topography is recorded along the MEMS excitation period for each mode shape. The full-field measurement allow the MEMS designer to characterize :

  • Displacement amplitude
  • Mirror surface deformation
  • Mode shapes

More details please visit another application page MEMS Micromirror


Micromirror : 3D representation of vibration modes
Vibration Map @ 19 kHz. Courtesy of Lemoptix, Lausanne, Switzerland
Vibration Map @ 491 kHz. Courtesy of Lemoptix, Lausanne, Switzerland
Vibration Map @ 773 kHz. Courtesy of Lemoptix, Lausanne, Switzerland

Modal frequency determination in Vacuum

The DHM® unique optical configuration and the large objective collection enables measurement through glass viewport.

Two methods are used to compute modal frequency :

  • Bode diagrams by performing a frequency scan
  • Fourier Transform by exciting the device with broadband signal
Bode Diagram : amplitude comparison between atmospheric and vacuum condition

Fast In-plane displacement

Optical shutter is in-plane optical MEMS : silicon parts move in liquids between two glasses. Optimization of in-plane performance requires minimization of out-of-plane displacement.

In- & out-of-plane displacement are recorded simultaneously

The DHM®  records time-sequence of 3D topographies up to 25 MHz, this unique set of data is recorded with a single instrument. It is the sole instrument that measures the evolution of 3D topography along the excitation period.  This unique set of data contains also analog and digital electrical inputs.

Recording of in- & out-of-plane is perfectly synchronized, there is no bias introduce by a scanning mechanism or measurement combination.

  • In-plane displacement
  • Out-of-plane displacement

Measurement in liquid

The silicon elements are moving between two glasses in liquid. Compensation of liquid and glass thickness is possible thanks to the DHM®  unique optical configuration.

Visit our catalog of objective lens.

Time-sequnece of 3D topographies : both, in- & out-of-plane, are recorded simultaneously
Optical Shutter : In & out-of-plane displacement