The transmission-configured Digital Holographic Microscope (DHM®) from Park Systems boasts a distinct experimental setup ideally suited to analyzing light-transmitting samples in material sciences and biology.
DHM-T combined with an electrophysiological setup. Image Credit: Park Systems
Biological Imaging
Label-Free Biological Microscopy
DHM® facilitates the non-toxic quantitative assessments of individual cells and cultures up to confluence, including:
- Time-lapse
- Diagnostic
- Multi-well plate screening
Investigation of Previously Unexplored Biological Processes
It is possible to interpret the quantitative phase measurement offered by DHM® based on a number of biological processes, including:
- Intracellular concentration
- Channel activity
- Morphology changes
- Cell viability
Multimodal Imaging Capabilities
An optional module allows users to perform DHM® and fluorescence measurements simultaneously. This enables:
- The correlation of DHM® measurements with other widely used measurement techniques
- A reduction in the need for fluorescence labeling
- Enhanced understanding of cellular mechanisms
Optical Profilometry
Transmission Configured Optical Profilometer
The transmission DHM® enables measurement of a diverse range of sample attributes, including:
- Variable thicknesses
- Sample optical topography
- Birefringence
- Refractive indices and concentrations
- Size and positioning of internal structures and defects
Investigations into Innovative Devices and Materials
Rapid dynamical measurement has been shown to prove beneficial to a wide range of applications, including:
- Wettability of coatings and structures
- Micro-optics
- Micro-fluidics
- Fluid and gas dynamics
- Biophysics
- Crystallization and dissolution
- Particle velocimetry
- Stress and constraints analysis
- Liquid Crystal Displays (LCD)
Time sequence of 3D optical map of quantitative phase measurement, limited by camera rate: division of HeLa cells. Image Credit: Park Systems
DHM® Technology
Transmission DHM®. Image Credit: Park Systems
Patented Digital Holographic Microscopy (DHM®) technology uses a microscope fitted with a digital camera to capture holograms that have been generated by interference between an internal reference beam and the sample beam.
Numerical processing is applied to these holograms to produce a 3D optical map of the specimen being analyzed.
The laser wavelength intrinsically defines DHM®’s vertical calibration. Accurate and reproducible data is produced with interferometric resolution (such as subnanometric vertical resolution) and a lateral resolution limited by the choice of microscope objective.
Thanks to advanced numerical processing of recorded holograms, whether concurrently or post-measurement, fine focus can be achieved without manual sample height adjustment.
Two different Transmission DHM® configurations are available, with each differing in the number of wavelengths:
- T1000 models are set up with a single wavelength, making them ideally suited to measuring clear material samples with smooth surfaces and examining simple living cells.
- T2100 models are set up to measure at two wavelengths simultaneously, expanding measurement capability.
Technical Specifications
Source: Park Systems
| System |
| DHM models |
T1000 |
T2100 |
| Number of laser sources |
1 |
2 |
|
Operating wavelength (± 1.0 nm)
|
666 nm |
666 nm, 794 nm |
| Laser wavelength stability |
0.01 nm / °C at 675 nm |
| Sample stage |
Manual or motorized XYZ stages 114 mm x 76 mm x 38 mm travel range |
| Objectives |
Magnification 1.25x to 100x, standard, high NA, long working distance, water/oil immersion |
|
Objective & condenser turret
|
6 positions |
| Computer |
Workstation with the latest multicore Intel® processor, high-performance graphics card, optimized and configured for DHM with a screen min 21 inch and a mouse |
| Software |
Proprietary Koala software based on C++ and .NET
Additional optional software modules are vailable for advanced analysis |
| Data compatibility |
Measurement data recorded in bin format, exportable in .txt format, recorded and reconstructed images exportable in .tif format or .txt array |
| Performance |
| Measurement mode |
Single wavelength at 666 nm |
Short synthetic wavelength at 8 μm 4 |
| DHM models |
T1000, T2100 |
T2100 |
| Accuracy 1 [nm] |
1.04 |
1.0 / 5.04* |
| Vertical resolution 2 [nm] |
2.04 |
2.0 / 10.04* |
| Repeatability 3 [nm] |
0.024 |
0.02 / 0.054* |
| Vertical measuring range |
up to 500 μm4 |
up to 500 μm4 |
| Max. height of steps with sharp edges6 |
up to 1.0 μm4
up to 3.5 μm5 |
up to 7.0 μm4
up to 22 μm5 |
| Vertical calibration |
Determined by an interferometric optical filter, ±0.1 nm |
| Acquisition time |
Standard: 500 μs (optional 10 μs) |
| Acquisition rate |
Standard: 190 fps (1024 x 1024 pixels) (optional up to 100,000 fps). |
| Reconstruction rate |
Up to 25 fps 1024 x 1024 pixels hologram (data analysis dependent) (optional up to 60 fps) |
| Lateral resolution |
Objective dependent, down to 300 nm** |
| Field of view |
Objective dependent, from 66 μm x 66 μm up to 5 mm x 5 mm** |
| Working distance |
Objective dependent, from 0.3 to 18 mm** |
| Digital focusing range |
Up to 50x depth of field (objective dependent) |
| Sample illumination |
Down to 1 μW/cm2 |
| Power requirements |
| Input voltage |
85-260 VAC – 50/60 Hz |
| Power requirements |
max. 250 W |
| Dimensions & weight |
| Dimensions (L x W x H) |
600 x 350 x 500 mm |
| Weight |
30 kg |
1 As demonstrated by taking the temporal standard deviation on 1 pixel over 30 measurements
2 Defined as twice the accuracy
3 As demonstrated by taking the one sigma Rq value of 30 repeatability measurements without sample
4 Converted value for measurements in air and with sample refractive index n = 1.5
5 Converted value for measurements in water and with sample refractive index n = 1.5
6 Depends on the laser source(s) and operating wavelength(s)
* With / Without single wavelength mapping
** Objectives specifications on www.lynceetec.com/microscope-objectives
Transmission DHM® combined with a Fluorescence module. Image Credit: Park Systems
DHM® systems are compatible with a wide range of optional accessories and systems, including:
- A dipping tip suitable for measuring immersion in well plates and open chambers
- A fluorescence module to combine DHM and epifluorescence measurements
- A high-speed camera allowing an increased measurement range
- Goals with extra-LWD, cover-glass correction, for immersion, etc.
- A motorized stage for automation and stitching
- A remote TCP/IP module for DHM automation and remote control
- A stroboscopic apparatus suitable for MEMS examination