Digital Holography
Description
The Reflection DHM series (DHM®-R1000, DHM®-R2100 and DHM®-R2200) are reflection configured holographic microscopes. They are ideal for measuring totally and partially reflecting objects. Their ability to work with low reflective interfaces (down to less than 1% reflectivity), make them ideal instruments for accurate optical topography measurements on a large variety of samples.
With their high acquisition rate and ease of use, DHM® instruments allow rapid routine inspections, automated industrial quality control as well as innovative R&D applications, particularly for dynamic observations. There are three configurations available, defined by the number and combination of wavelengths:
- R-1000 series: single laser source.
- R-2100 series: dual laser sources.
- R-2200 series: three laser sources.
The reflection DHM® are compatible with the optional Stroboscopic module and the post-analysis software for MEMS analysis and Reflectometry analysis. Each DHM® can be delivered with its own structure to hold it, or as a head only, to be mounted on other structures or on production lines. The DHM® are compatible with a large range of optional motorized stages. Lyncée Tec has developed the DHM® technology from its invention to its maturity. It has the competence and flexibility to offer you customized and OEM systems.
R1000 Series
The DHM®-R1000 instruments are configured with a single wavelength to provide real-time measurements of samples with sub-nanometer resolution for step heights up to 340 nm within the 200µm live vertical range. It is the simplest model of the DHM®-R series, and is particularly cost effective as well as extremely easy to use. It is the ideal tool for measuring smooth surfaces with small local slopes, topography of samples with steps or discontinuities with height smaller than 300 nm.
R2100 Series
The DHM®-R2100 instruments are configured for measuring simultaneously at two wavelengths. This configuration enables to achieve true real-time measurements of sharp steps up to 2.1 μm high keeping nanometer vertical resolution within the 200 μm vertical range.
The innovating optical schema is composed of two laser sources with common object path that allows:
- An increase of the measurement range to step heights of up to 2.1 µm, without any scanning or wavelength switch
- True real-time measurements for both single and dual wavelengths modes and full frame phase and intensity images at video rate
- Sub-nanometer resolution over the complete vertical range using mapping algorithms
DHM® R2100 family 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 2.1 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, etc. 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 two 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.
The sub-nanometer vertical resolution of the monochromatic wavelength measurements can be kept over the dual wavelength measurement range thanks to powerful mapping algorithms combining the synthetic and monochromatic wavelengths data.
The simultaneous recording of data results in the fastest measurements 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 physics behind the dual wavelength DHM®
The R2100 instruments provide simultaneous dual wavelength measurements. The interference between the two sources λ_1 and λ_2 creates a synthetic wavelength Λ that allows real-time measurements of 3 µm high steps with a sub-nanometer resolution within the 200µm live vertical range .
Λ= (λ1 x λ2) / |λ1 – λ2| , Λ≫λ1, λ2
Each wavelength can be used individually.
R2200 Series
The DHM®-R2200 instruments are configured with three wavelengths extending true real-time measurements of sharp steps up to 12 μm high with nanometer vertical resolution within the 200 μm vertical measurement range.
The DHM® R2200 instruments reach a new level for real-time measurements in interference microscopy. Their innovating optical schema is composed of common object path and camera and holds three light sources. These three light sources allow two different simultaneous dual wavelengths combination, i.e. two synthetic wavelengths that allow:
- An increase of the measurement range to step heights of up to 12 µm, without any scanning or wavelength switch
- True real-time measurements for both single and dual wavelengths modes and full frame phase and intensity images at video rate
- Sub-nanometer resolution over the complete vertical range using mapping algorithms
- Dual wavelength measurements providing the same tools, ease-of-use and insensitivity to vibrations as single wavelength
DHM® R2200 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 12 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, etc. 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.
The R2200 series integrates a third light source alternating with the second one. It thus comprises a short and a larger synthetic wavelength that further extends the measurement range. The DHM® R2200 model has synthetic wavelengths of 4.2 and 24 μm for step heights up to 2.1 and 12 μm.
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.
The simultaneous recording of data results in the fastest measurements 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.
The physics behind the dual wavelength DHM®
The interference between two sources creates a large synthetic wavelength Λ that allows real-time measurements up to 12 µm high steps with a sub-nanometer resolution within the 200µm live vertical range. The interference between the other two sources creates a short synthetic wavelength Λ that allows real-time measurements up to 2.1 μm high steps.
Λ= (λ1 x λ2) / |λ1 – λ2| , Λ≫λ1, λ2
Mapping algorithms ensure to keep the monochromatic sub-nanometer resolution over the complete vertical measurement range. Each wavelength can be used individually.
Description
The Transmission DHM®-Series are designed for measuring transparent or semi-transparent samples. There are available in two configurations : DHM® T-1000 operating with a single laser, and DHM® T-2100 operating with two lasers.
In life sciences
DHM®-T provides precise Quantitative Phase Measurements (QPM) of living cell cultures up to confluence, without the use of any contrast agent and with very low illumination power. The DHM®-T is an ideal instruments for high content screening, time lapse measurements and diagnostic. Used in conjunction with the optional fluorescence module, it enables simultaneous DHM® and fluorescence measurements. It is compatible with motorized stages. and with a large choice of accessories for working with living cells.
In material sciences
DHM®-T measures specimen shape and surface, as well as material optical parameters, internal structure and defects. It is an ideal tool for characterization of micro optics, providing shape, refractive index and optical transfer function. Refractive index liquids can be used for characterization of steep slope samples like micro-corner cubes and Fresnel lenses among other. Other major applications are characterization of micro-fluidics devices and 3D- particle flow velocimetry. Systems are compatible with motorized stages, stroboscopic module and the post-analysis software for MEMS analysis.
Description
The highspeed DHM® operates with a single wavelength and can be configured in either transmission or in reflection.
Its optical set up and laser source have been specifically optimized to operate with the highspeed camera FASTCAM NOVA by Photron. This system offers hologram recording rates up to 12’800 frames per second (fps) at megapixel resolution, 40’000 fps at a resolution of 512×512 pixels, and 116’000fps at 256×256 pixels.
A dedicated and intuitive software interface, fully integrated in our Koala acquisition and analysis software, enables to control the highspeed camera parameters (acquisition framerate, shutter), to handle the different camera trigger modes, to access optimally the camera internal memory buffer, to replay an acquired sequence, to select the relevant frames, and eventually to export the selected ones.
The highspeed DHM® system enables novel research among others in the fields of energy harvesting, impact analysis, fluid interfaces, transients, stress analysis, evaporation, drying, absorption, desorption, and dissolution phenomena, etc.
