Standard and high-resolution Fizeau interferometers
Hardware
Fizeau interferometers are often used to exactly measure the surface characteristics of optics such as lenses or mirrors. The development team of Äpre Instruments
The development team at Äpre Instruments can rely on decades of experience in the interferometer industry and has put all the knowledge gained into the development of its own modern Fizeau interferometers and light sources.
In the devices of the S and Ä series the optical bench is completely separated from the electronics board. State-of-the-art digital cameras are used both for aligning the optical axis and for measuring the surface. The image resolution can be configured up to 9 megapixels. Communication with the PC takes place via USB3.
Software Reveal
Not only the hardware but also the software comes completely from Äpre Instruments. In digital interferometry, the software for controlling and evaluating the data is at least as important and decisive as the hardware. The software developers at Äpre Instruments have therefore worked for years to write software that is as user-friendly as possible for use in optics manufacturing and at the same time extremely powerful.
View software
Spectral Controlled Interferometry
All standard and high-resolution Fizeau interferometers from Äpre Instruments are equipped with a frequency-stabilized SLM 633 nm HeNe laser. The measurement technique can be carried out using either traditional phase shift, vibration-tolerant phase shift or the vibration-insensitive carrier fringe method. In addition, each interferometer can be connected to Äpre Instruments’ own specially developed light source, which can be used to measure different surfaces separately using the so-called SCI technology (Spectrally Controlled Interferometry).
View SCI light source
For more in-depth reading on the subject, we recommend this article.
Fizeau interferometers for surface and wavefront metrology
S-Series 1MP
S50|1MP | S100|1MP | S150|1MP | |
---|---|---|---|
System Overview | |||
Output Diameter | 51 mm (2 inch) | 102 mm (4 inch) | 153 mm (6 inch) |
Optical Centerline | 108 mm (4.25 inch) | 108 mm (4.25 inch) | 133 mm (5.24 mm) |
Focus Range (position readout) | ±0.5 meters | ±2 meters | ±4.5 meters |
Interferometer size (L x W x H) | 63 x 29 x 18 cm | 70 x 32 x 25 cm | 90.2 x 40.8 x 23.9 cm |
Weight | 25 kg (55 lbs) | 33 kg (73 lbs) | 50 kg (110 lbs) |
Measurement Techniques | Fast/Sensitive Spectral Synchronous, Vibration-Tolerant PSI Plus Vibration-Insensitive Carrier Fringe |
||
Alignment System | 2-spot with reticle with 2° capture range | ||
Light Source | SCI SpectrÄ 2.0, HeNe Laser, and ÄTLas Wavelength Shifting | ||
Laser Frequency Stability | <0.0001 nm | ||
Temporal coherence Length | SCI SpectrÄ 2.0 ≤2 meters, HeNe Laser >100 meters, ÄTLas ≤3 meters | ||
Output Polarization | Circular (Linear optional for birefringent part measurement) | ||
Camera Resolution | 1022 x 1022 | ||
Camera frame rate (max) | 90 Hz (25 Hz with SCI source) | ||
Shutter Speed – shortest | 9 µs | ||
Camera digitization | 8 bit | ||
Computer & Software | High-Performance PC, Windows11, 64-bit OS & REVEAL Software | ||
Mounting Configurations | Horizontal or Vertical | ||
Performance | |||
Image Resolution (Detector Limited) | 100 µm (10 l/mm) | 200 µm (5 l/mm) | 300 µm (3.3l/mm) |
Image Distortion | <0.1% | ||
Fringe Resolution | >300 fr/aperture | ||
Retrace Error3 @ 256 fringes | < λ/15 | ||
RMS Simple Repeatability1 | <0.6 nm RMS 2σ | ||
RMS Wavefront Repeatability2 | <0.6 nm RMS 2σ | ||
Measurable Part Reflectivity | 0.1%to 40% direct and >41% with attenuation filter or coatings | ||
Environment | |||
Temperature | 15º C to 30º C | ||
∆T/∆t | <1.0º C/15 min | ||
Humidity | 5 to 95% relative, non-condensing | ||
Vibration Isolation | Isolation System recommended for VTPSI |
2) RMS Wavefront Repeatability Test: Measure 36 sequential Measurements (M1, M2,...M30) each consisting of 16 averages. Then average all 36 measurements create a synthetic reference, "Ref", RMS wavefront repeatability equals the 2X the standard deviation of all 30 Ref - Mn results.
3) Retrace Error is defined as the PV residual error between a nulled measurement (the reference), subtracted from a measurement with 500 fringes of tilt, and expressed by the first 36 Zernike polynomials
4) λ/20 optionally available
5) Resolution is detector limited at 800 lines/aperture
Specifications subject to change without notice
S-Series 4MP
S50|4MP | S100|4MP | S150|4MP | S300 | 4MP | |
---|---|---|---|---|
System Overview | ||||
Interferometer Type | Fizeau Configuration | |||
Output Diameter | 51 mm (2 inch) | 102 mm (4 inch) | 153 mm (6 inch) | 306 mm (12 inch)6 |
Optical Centerline | 108 mm (4.25 inch) | 108 mm (4.25 inch) | 133 mm (5.24 mm) | Specify |
Focus Range | ±0.5 meters | ±2 meters (encoded) | ±4.5 meters (encoded) | ±2 meters (position readout) |
Interferometer size (L x W x H) | 63 x 29 x 18 cm | 70 x 32 x 25 cm | 90.2 x 40.8 x 23.9 cm | 76 x 40 x 50 cm |
Weight | 25 kg (55 lbs) | 33 kg (73 lbs) | 50 kg (110 lbs) | TBD |
Phase Measurement Techniques | Fast/Sensitive Spectral Synchronous, Vibration-Tolerant PSI Plus Vibration-Insensitive Carrier Fringe | Fast/Sensitive Synchronous, Vibration-Tolerant PSI Plus Vibration-Insensitive Carrier Fringe |
||
Alignment System | 2-spot with reticle with 2° capture range | |||
Three optional light sources | SCI SpectrÄ 2.0, HeNe Laser, and ÄTLas Wavelength Shifting | |||
HeNe Laser Frequency Stability | <0.0001 nm | |||
Temporal coherence Length | SCI SpectrÄ 2.0 ≤2 meters, HeNe Laser >100 meters, ÄTLas ≤3 meters | |||
Output Polarization | Circular (other options available) | Circular or Linear, for birefringent materials | ||
Camera Resolution | 2040 x 2048 pixel | 2044 x 2044 | ||
Camera frame rate (max) | 180 Hz @ 2040 X 2048 pixels | ≤180 Hz (source dependent) | ||
Shutter Speed – shortest | 9 µs | |||
Camera digitization | 8 bit | 12 bit | ||
Computer & Software | High-Performance PC, Windows 10 64-bit OS & REVEAL Software | |||
Mounting Configurations | Horizontal or Vertical | Horizontal or Vertical or Adjustable | ||
Accessories | Optical Accessories and Mounts Available | n/a | ||
Performance | ||||
Image Resolution | 5 63 µm 16 l/mm | 5 125 µm 8 l/mm | 5 188 µm 5.3 l/mm | 230 µm (4.2 l/mm) |
Image Distortion | <0.06% | |||
Fringe Resolution | ≥600 fr/aperture | >500 fr/aperture | ||
Retrace Error3 @ 511 fringes | ≤ λ/154 | |||
RMS Simple Repeatability1 | <0.6 nm RMS 2σ | |||
RMS Wavefront Repeatability2 | <0.6 nm RMS 2σ | |||
Measurable Part Reflectivity | 0.1%to 40% direct and >41% with attenuation filter or coatings | 0.5% to 100% Specify | ||
Environment | ||||
Temperature | 15º C to 30º C | |||
∆T/∆t | <1.0º C/15 min | |||
Humidity | 5 to 95% relative, non-condensing | |||
Vibration Isolation | Isolation System recommended for VTPSI | Isolation System recommended for PSI |
2) RMS Wavefront Repeatability Test: Measure 36 sequential Measurements (M1, M2,...M30) each consisting of 16 averages. Then average all 36 measurements create a synthetic reference, "Ref", RMS wavefront repeatability equals the 2X the standard deviation of all 30 Ref - Mn results.
3) Retrace Error is defined as the PV residual error between a nulled measurement (the reference), subtracted from a measurement with 500 fringes of tilt, and expressed by the first 36 Zernike polynomials
4) λ/20 optionally available
5) Resolution is detector limited at 800 lines/aperture
6) Up to 310mm is available on special request
Specifications subject to change without notice
Ä-Series 4MP
Ä50|4MP | Ä100|4MP | Ä150|4MP | |
---|---|---|---|
System Overview | |||
Interferometer Type | Fizeau Configuration | ||
Function | Surface, wavefront, TTV, and angle metrology | ||
Output Diameter | 51 mm (2 inch) | 102 mm (4 inch) | 153 mm (6 inch) |
Optical Centerline | 108 mm (4.25) | 108 mm (4.25 inch) | 133 mm (5.24 mm) |
Focus Range (encoded) | ±0.5 meters | ±2.0 meters | ±4.5 meters |
Interferometer size (L x W x H) | 63 x 29 x 18 cm | 70 x 32 x 26 cm | 90.2 x 40.8 x 23.9 cm |
Weight | 25 kg (55 lbs) | 33 kg (73 lbs) | 50 kg (110 lbs) |
Phase Measurement Techniques | Spectral Synchronized, Vibration Tolerant & Vibration Insensitive Carrier Fringe | ||
Alignment System | 2-spot with reticle with 2° capture range | ||
Three optional light sources | Laser, SpectrÄ 2.0 and Wavelength Shifting | ||
HeNe Laser Frequency Stability | <0.0001 nm | ||
Temporal coherence Length | HeNe Laser >100 meters, SpectrÄ 2.0 > 2 meter | ||
STAR: Spatial Coherence Control | Reduces coherent noise when averaging Add SpectrÄ for true White Light Fizeau Performance6 |
||
Output Polarization | Circular (Other options available) | ||
Camera Resolution | 2040 x 2040 pixel | ||
Camera frame rate (max) | 180 Hz | ||
Shutter Speed – shortest | 9 µs | ||
Camera digitization | 8 bit | ||
Computer & Software | High-Performance PC, Windows 10 64-bit OS & REVEAL Software | ||
Mounting Configurations | Horizontal or Vertical | ||
Accessories | Optical Accessories and Mounts Available | ||
Performance | |||
Image Resolution5 | 63 μm 16 l/mm | 85 µm 12 l/mm | 125 µm 8 l/mm |
Image Distortion | <0.06% | ||
Fringe Resolution | ≥600 fr/aperture | ||
Retrace Error3 @ 512 fringes | ≤ λ/154 | ||
RMS Simple Repeatability1 | <0.6 nm RMS 1σ – with NO averaging | ||
RMS Wavefront Repeatability2 | <0.6 nm RMS 1σ – with NO averaging | ||
Measurable Part Reflectivity | 0.1%to 40% direct and >41% with attenuation filter or coatings | ||
Environment | |||
Temperature | 15º C to 30º C | ||
∆T/∆t | <1.0º C/15 min | ||
Humidity | 5 to 95% relative, non-condensing | ||
Vibration Isolation | Isolation System recommended for VTPSI |
1) RMS Simple Repeatability is defined as 1X the standard deviation of the RMS for 36 sequential measurements (0 averages ) of a short, 1 mm plano cavity
2) RMS Wavefront Repeatability is defined as the mean RMS difference between a synthetic reference (defined as the a verage of a ll 36 sequential
measurements) and each measurement plus 1X the standard deviation
3) Retrace Error is defined as the PV residual error between a nulled measurement (the reference), subtracted from a measurement with 500 fringes of tilt, and
expressed by the first 36 Zernike polynomials
4) λ/20 optionally available
5) Resolution is detector limited at 800 lines/aperture
6) STAR is Spatial and Temporal Artiface Reduction for unique White Light Fizeau performance, with laser alignment ease
Specifications subject to change without notice
Ä-Series 9MP
Ä100|9MP | Ä150|9MP | |
---|---|---|
System Overview | ||
Interferometer Type | Fizeau Configuration | |
Function | Surface, wavefront, TTV, and angle metrology | |
Output Diameter | 102 mm (4 inch) | 153 mm (6 inch) |
Optical Centerline | 108 mm (4.25 inch) | 133 mm (5.24 mm) |
Focus Range (encoded) | ±2.0 meters | ±4.5 meters |
Interferometer size (L x W x H) | 70 x 32 x 26 cm | 90.2 x 40.8 x 23.9 cm |
Weight | 33 kg (73 lbs) | 50 kg (110 lbs) |
Phase Measurement Techniques | Fast/Sensitive Spectral Synchronous, Vibration-Tolerant PSI Plus Vibration-Insensitive Carrier Fringe |
|
Alignment System | 2-spot with reticle with 2° capture range | |
Three optional light sources | SCI SpectrÄ 2.0, HeNe Laser, and ÄTLas Wavelength Shifting | |
HeNe Laser Frequency Stability | <0.0001 nm | |
Temporal coherence Length | SCI SpectrÄ 2.0 ≤2 meters, HeNe Laser >100 meters, ÄTLas ≤3 meters | |
STAR: Spatial Coherence Control | Reduced coherent noise when averaging Add SpectrÄ for for low temporal & spatial coherence performance6 |
|
Output Polarization | Circular (Linear optional for birefringent part measurement) | |
Camera Resolution | 3000 x 3000 pixel | |
Camera frame rate (max) | 90 Hz | |
Shutter Speed – shortest | 9 µs | |
Camera digitization | 8 bit | |
Computer & Software | High-Performance PC, Windows 10 64-bit OS & REVEAL Software | |
Mounting Configurations | Horizontal or Vertical | |
Accessories | Optical Accessories and Mounts Available | |
Performance | ||
Image Resolution5 | 85 µm 12 l/mm | 125 µm 8 l/mm |
Image Distortion | <0.06% | |
Fringe Resolution | ≥900 fr/aperture | |
Retrace Error3 @ 512 fringes | ≤ λ/154 | |
RMS Simple Repeatability1 | <0.6 nm RMS 2σ | |
RMS Wavefront Repeatability2 | <0.6 nm RMS 2σ | |
Measurable Part Reflectivity | 0.1%to 40% direct and >41% with attenuation filter or coatings | |
Environment | ||
Temperature | 15º C to 30º C | |
∆T/∆t | <1.0º C/15 min | |
Humidity | 5 to 95% relative, non-condensing | |
Vibration Isolation | Isolation System recommended |
1) RMS Simple Repeatability Test: The RMS for 36 sequential measurements with each measurement the average of 16 measurements each of a short <2 mm plano cavity
2) RMS Wavefront Repeatability Test: Measure 36 sequential Measurements (M1, M2,...M30) each consisting of 16 averages. Then average all 36 measurements create a synthetic reference, "Ref", RMS wavefront repeatability equals the 2X the standard deviation of all 30 Ref - Mn results.
3) Retrace Error is defined as the PV residual error between a nulled measurement (the reference), subtracted from a measurement with defined fringes of tilt, and expressed by the first 36 Zernike polynomials
4) λ/20 optionally available
5) Resolution is detector limited at 80% of Nyquist or 1200 lines/aperture for a 9MP sensor.
6) Spatial and Temporal Artifact Reduction for unique low noise performance when combined with SCI SpectrÄ source, with laser alignment ease
7) Design performance as modeled in Zemax wtih 2 meter cavity length
Specifications subject to change without notice