Overview:
A white light interferometer, used e.g. in the context of low-coherence interferometry, is an interferometer, typically a Michelson interferometer, which works with a white light source, i.e. with a light source with broad optical bandwidth. The light source does not necessarily operate in the visible spectral range, really generating white light. Its temporal coherence has to be fairly small, whereas a high spatial coherence is normally needed. The high spatial coherence combined with a broad bandwidth can most easily be obtained by launching light from a bulb into a single-mode fiber, but this leads to a very small launched power. The radiance (brightness) can be increased by many orders of magnitude by using a superluminescent source such as a superluminescent diode. In some cases, wavelength-swept tunable lasers are used.
The Phase shift MicroXam is a non contact 3D surface profiler which measures roughness, finish and texture of surfaces. Interferometres ude the natural wave properties of light , reflected from a surface, to map the tinest surface height variations. Its main features are:
- Comprehensive graphical software for the aquisition, analysis, manipulation, and visualisation of data.
- Calculation of surface statistics including summit and valley analysis
- Fourier and autocovariance analysis and surface filtering
- Polynomial fitting, data filtering, scaling, masking and interpolation
- Interactive zoom
- X-Y and line segment profiles
- 3D wire, hybrid and solid plots
- Area difference plot step height measurement
- Fourier analysis for visualising and chacterising periodic structures in surface maps
Technical Specifications:
- Objective Magnification :50x
- Numerical Aperture :0.55
- Measurment Area :82×62um, 132×100um, 165×125um, 264×200um
- Spatial Sampling :0.22×0.26um
- Working Distance :3.4mm
- Depth of Focus :1.16um
- Maximum Surface Slope :22.6º
- RMS Repeatability (Phase shifting mode) :0.1nm
- RMS Repeatability (Extended mode) :0.1nm
- Vertical scan range :30 microns, 100 microns or 5mm
Applications:
- Biomedical Optics eg.contact lens surface measurement
- Hard Disk and Magnetic Media eg. 3D characterisation
- Optics eg. telescope manufacture (Hubble telescope)
- Polymer surface roughness
- Bearing surface wear
- Silicon Wafer Step Height
- Thick Film Conductor Thickness