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DHM R2000 Reflexion / Transmission-Digital Holographic Microscopy

DHM R2000 Reflexion / Transmission

Real-time measurements extended to 15 μm high steps keeping nanometer vertical resolution

A new level is reached for real-time measurements in interference microscopy. The DHM R2200 family performs measurements at two wavelengths simultaneously. Its innovating optical schema is composed of two nested DHM with common object path and camera and holds three light sources. This unique feature, offered by DHMs' principle, provides a dual wavelength real-time measurement mode with two synthetic wavelengths that allows:

Dual wavelength mode: keep the speed and ease-of-use

DHM R2200 family has the same features and capabilities than the DHM R2100 series while including three light sources. It enables two interferences to take place simultaneously onto the same camera. Both are recorded on the same hologram and then independently reconstructed. They are combined at video rate to extend the measurement range to 15 microns as if the sample was imaged with a single wavelength, called synthetic wavelength, equivalent to the low frequency beating of the two monochromatic wavelengths. Working in dual wavelength mode is identical as in single wavelength. It keeps the same ease-of-use and facilities, such as sequences, roughness measurements, time monitoring,... Depending on your sample height, real-time measurements can be performed on either single monochromatic wavelengths data or on their synthetic combination. Switching between the measurement ranges is possible within a single acquisition as all the information is recorded simultaneously in the hologram and the measurements computed out of it.

Three light sources: higher vertical range

The R2200 series integrates a third light source alternating with the second one. It thus comprises a second larger synthetic wavelength that further extends the measurement range. The DHM R2201 model has synthetic wavelengths of 6 and 30 μm for step heights up to 3 and 15 μm.

Mapping: keep the vertical resolution

The sub-nanometer vertical resolution of the monochromatic wavelength measurements can be kept over dual wavelength measurement ranges thanks to powerful mapping algorithms combining the synthetic and monochromatic wavelengths data. For short synthetic wavelengths mapping is performed out of a single acquisition. For longer synthetic wavelengths, a short synthetic wavelength measurement is also required for mapping. Alternate measurements in long and short dual wavelengths are therefor performed (acquisition time: 500 ms).

The simultaneous recording of data results in the fastest measurements over microns in interference microscopy. It avoids any blurring due to acquisition time and thus ensures precision and robustness toward external vibrations. The real-time display of the measurements guaranties the ease-of-use and efficiency of DHM. The measurement range can further be increased to the millimeter range with the vertical coherence scanning module.

It is compatible with the optional Lyncée Tec stroboscopic module in single wavelength and different manual or motorized stages. Other synthetic wavelengths are available allowing higher measurement ranges without mapping or stroboscopic compatibility.