Shack-Hartmann wavefront sensor .

If Charles Darwin wasn’t thinking of the Shack-Hartmann wavefront sensor when he wrote his theory of evolution in 1838, it’s only because they hadn’t yet been invented. Since then, wavefront analysis technique has followed a steady evolution, accumulating inherited advantages combined with rapid adaptive leaps over almost a century, to become an optimum solution for modern optical metrology.

1900, 1st original idea by Hartmann

Around 1900, Johannes Franz Hartmann developed the Hartmann plate, consisting of an array of holes, which he used in combination with photographic plates to interpolate wavefront slopes and align telescopes.

 

1971, improvement by Shack (& Platt)

In 1971, Roland Shack and Ben Platt developed an optimized design for the Hartmann plate in which the array of holes is replaced by a much more efficient array of microlenses that concentrates light instead of widely blocking it, as with the mask.

Þ Combined with the advent of CCD cameras, this new approach has made the technique much faster, easier to use and adapted to “low light” applications such as astronomy.

Since then, the use of Shack-Hartmann sensors in optical metrology has continued to grow as they started to be used for laser testing, adaptive optics, ophthalmology for example.

 

1996, 1st commercial absolute wavefront measurement

Imagine Optic is established to materialize the vision of its cofounders: propose a reliable, easy to use and versatile tool for optical metrology at a time where only established alternative was the heavy, restrictive Fizeau interferometer.

Þ This is how the first Shack-Hartmann wavefront sensor offering live calibrated absolute measurement is commercialized as world premiere.

 

2001, first self-illuminated Shack-Hartmann

The LIP is born by combining our Shack-Hartmann wavefront sensor with an illumination feature in a built-in optomechanical platform.

Þ It optimizes optical quality and compactness of the solution in a ready to use to for transmission and reflection characterization of component.

 

2003, another patent

Imagine Optic turns the square apertures of the Hartmann plate, avoiding cross talk between adjacent sampling points.

Þ It allows to increase resolution and sampling of our HASO EUV Hartmann wavefront sensor operating at 248 nm.

 

2010, the advent of CMOS

Integration CMOS cameras as detectors for the wavefront sensors in replacement of the good old CCD.

Þ Customers benefit from faster and more sensitive sensors.

 

2015, broadband sensors

First Imagine Optic broadband Shack-Hartmann wavefront sensor offering absolute calibrated measurement in a wide 350-1100 nm spectral range with the HASO4 BROADBAND.

Þ Imagine Optic sensor precision of lambda/100 is now available for achromatic measurements at any wavelength

 

2017, instant setup feature

Invention of the SpotTracker  which avoid preliminary alignment procedure to make optical setup easier and quicker.

Þ It brings absolute tilt measurement and follow up over large variations unlike lateral shearing interferometers.

 

2020, resolution breakthrough

Imagine Optic moves/transposes and optimizes Onera’s experts research on LIFT technology to a commercial off-the-shelf solution

Þ Ultra High Resolution becomes available to Shack-Hartmann wavefront sensors with HASO LIFT 680 with a resolution of 680×504 phase points which is unheard of!

 

2022, an Optical Engineer Companion for the lab

 

Launch of the OEC : Imagine Optic makes its wavefront sensors, beam adapter modules, illumination platform, metrology sources interconnectable modules such as LEGO® bricks.

Þ It provides versatility to create any optical configuration needed for metrology: any beam size, any divergence, any wavelength, transmission and reflection.

Imagine Optic metrology solutions then combines in a flexible optical lab tool that adapt to projects over time and can be upgraded function of future needs.

 

These innovations are only here to make your metrology more accurate, robust and easier to use. Stay tuned for more info about Shack-Hartmann wavefront sensor.  We are happy to discuss how they suit your needs. Reach us at sales@imagine-optic.com or through the contact form.

Understanding Shack-Hartmann Wavefront Sensor Technology

 

Shack-Hartmann wavefront sensors technology is a sophisticated optical method used to analyze and measure the wavefront of light. At its core, Shack-Hartmann wavefront sensing involves dissecting a wavefront into numerous smaller segments using a lenslet array, a key component of the Shack-Hartmann sensor. Each lenslet in this array focuses a part of the incoming wavefront onto a detector, typically a CCD or CMOS sensor. By examining the way these focal points are arranged on the detector, Shack-Hartmann wavefront sensors can accurately determine the shape and quality of the incoming wavefront.

In Shack-Hartmann wavefront sensing, any deviation of these focal points from their expected positions is indicative of wavefront distortions or aberrations. This is where the technology shines, as it can quantify these aberrations with high precision. The data gathered from these deviations are then processed through advanced algorithms to reconstruct a detailed map of the wavefront. This map is integral to identifying and correcting optical aberrations in a variety of settings, from astronomical telescopes to vision correction and laser system optimization.

The evolution of Shack-Hartmann wavefront sensors, marked by continual innovations and improvements, has made it a fundamental tool in optical metrology. Its ability to provide precise, real-time analysis of light wavefronts makes the Shack-Hartmann wavefront sensor an invaluable asset in advancing the field of optics and improving the performance and accuracy of optical systems worldwide.

Shack-Hartmann Wavefront Sensors: An In-Depth Guide

Introduction to Shack-Hartmann Wavefront Sensors

Shack-Hartmann wavefront sensing stands as a pinnacle in optical metrology, named after Johannes Franz Hartmann and Roland Shack. This sensor is integral for measuring wavefront shapes in diverse applications, from attenuated laser beams to starlight in optical telescopes, and is particularly crucial in adaptive optics systems.

Operational Principles of Shack-Hartmann Wavefront Sensing

The Shack Hartmann wavefront sensor operates on a straightforward principle. It consists of an array of microlenses and an image sensor positioned at the microlens array’s focal plane. This setup allows each lenslet to focus incoming light onto the sensor, with the spot’s position revealing the wavefront’s orientation.

Advanced Calculations and Algorithms in Shack-Hartmann Wavefront Sensors

Shack Hartmann wavefront sensing involves sophisticated calculations. Spot positions are determined by calculating the ‘center of gravity’ of the intensity distribution, allowing for high-resolution measurements. Furthermore, advanced algorithms are employed to enhance accuracy, especially under challenging conditions.

Determining Wavefront Distortions Using Shack Hartmann Sensors

The method for calculating wavefront distortions is a critical aspect of Shack Hartmann wavefront sensing. The orientation of the wavefronts is determined by the position shift of the spots, providing the basis for reconstructing the wavefront field.

Applications of  a Shack Hartmann Wavefront Sensor

Shack Hartmann wavefront sensors are versatile, finding applications in astronomical telescopes, optics characterization, ocular diagnostics, and laser beam characterization. Each application highlights the sensor’s ability to measure and analyze wavefront shapes accurately.

Specifications and Considerations in Shack-Hartmann Wavefront Sensors

Key specifications of Shack Hartmann wavefront sensors include measurement area, spatial resolution, angular range, and dynamic range. These factors play a vital role in the sensor’s performance and its suitability for various applications.

Conclusion: The Role of Shack-Hartmann Wavefront Sensing in Optical Metrology

Shack Hartmann wavefront sensing is a cornerstone in the field of optical metrology. Its precision, adaptability, and continuous evolution make it an indispensable tool in a wide range of optical applications, from studying the stars to refining laser technology.