Laser direct writing of rotationally symmetric high-resolution structures

Haefner, Matthias; Pruß, Christof

doi:10.1364/ao.50.005983

Cited by 15 publications

(7 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If the object point moves or, in the case of an SHS, the gradient of the segmented wavefront changes, all replicated spots move by the same amount (Fourier shift theorem). The CGH is optimized using the direct binary search algorithm 27 and is lithographically fabricated 28 in a clean room. Without multipoint replication, the position information is stored in just a few bright pixels.…”

Section: Basic Principle and Experimental Setupmentioning

confidence: 99%

Large dynamic range Shack–Hartmann wavefront sensor based on holographic multipoint generation and pattern correlation

Hartlieb,

Wang,

Rüdinger

et al. 2024

Opt. Eng.

View full text Add to dashboard Cite

A principle of a wavefront measurement sensor based on computer generated holograms is presented. In contrast to conventional Shack-Hartmann sensors, the wavefront is not sampled using a lens array but an array of subholograms. Each subhologram generates a multipoint pattern with unique point distribution on the camera fulfilling two tasks. First, by calculating the wavefront reconstruction for each of the multiple points, averaging improves the accuracy compared to a single point evaluation. Second, the dynamic range of the proposed sensor is enhanced due to the unique shape of each pattern. The assignment between pattern and subhologram can be achieved even for overlapping patterns by the use of digital image correlation. First results show that the averaged standard deviation is 12.5 nm, which corresponds to less than λ∕50, and the maximum angle of the incident wavefront is 8.7 deg. The sensitivity related to the aperture size is better than λ∕126.

show abstract

Section: Basic Principle and Experimental Setupmentioning

confidence: 99%

Large dynamic range Shack–Hartmann wavefront sensor based on holographic multipoint generation and pattern correlation

Hartlieb,

Wang,

Rüdinger

et al. 2024

Opt. Eng.

View full text Add to dashboard Cite

show abstract

“…The measurement of spheres, aspheres and freeform surfaces requires the capability to travel along high slopes with angles up to 80 • , while combining macro-geometries with micro-and nano-geometries using superposition. As an example, microstructures on a glass lens produced at ITO Stuttgart [36] even in a large curved area were measured with the focus probe in the NPM machine in Ilmenau (see figure 10).…”

Section: Prospects For Measurementmentioning

confidence: 99%

Recent developments and challenges of nanopositioning and nanomeasuring technology

Manske

Jäger

Hausotte

et al. 2012

Meas. Sci. Technol.

162

View full text Add to dashboard Cite

Rapid progress in several high-tech industries has significantly increased the need for dimensional micro- and nano-metrology. Structures to be measured are becoming more complex with smaller structure widths and higher aspect ratios in increasingly larger surface regions and potentially highly curved surfaces. Significant international effort can be seen to develop high-capacity measuring machines with nanometre precision in growing measuring ranges up to hundreds of millimetres. This paper begins with an outline of the requirements stemming from high-tech developments currently being done or expected in the future and discusses recent developments in the field of nanopositioning and nanomeasuring technology with respect to basic measurement approaches, laser interferometer systems. The large range of nanoprobe systems usable in nanomeasuring machines is discussed, such as optical focus sensors, white light interferometer microscopes, CCD camera microscopes using the depth from the focus method, tactile stylus probes, atomic force microscopes (AFMs) and 3D microprobes. The versatile properties of these sensors allow the machine to be used in many different metrological applications. The paper also introduces a multi-sensor approach using a microscope revolver. It concludes with an illustration of metrologically challenging measurements, e.g., scanning micro-structures of curved optical surfaces or performing AFM scans of very large regions with significant data volume.

show abstract

“…This automatically generates several lines at once. An added benefit is the high line density that can be achieved: line densities beyond 2000 LP/mm can readily be achieved with a 457 nm writing laser [3]. We have implemented a system that scans in polar coordinates, i.e.…”

Section: Scanning Beam Interference Lithographymentioning

confidence: 99%

Laser direct writing

Häfner

Pruß

2011

Optik & Photonik

Self Cite

View full text Add to dashboard Cite

Diffractive optics are compact and flexible optical elements with attractive properties that conventional refractive or reflective surfaces cannot deliver. While their fabrication is still challenging, the developments over the past years in both replication and mastering have advanced their application in fields like illumination shaping, metrology, laser beam forming, polarization shaping or fraud protection. A powerful tool for mastering is the technology of laser direct writing, initially developed for applications like mask production for lithography or mastering for optical data storage. In this contribution we present recent developments in laser direct writing technology for diffractive optics.The efficient fabrication of diffractive optics is of growing interest for many applications. While in conventional systems refraction or reflection on smooth optical surfaces is used to redirect the impinging light, a diffractive optical element uses diffraction on a microstructured surface to shape the incoming light into the desired output light field. The shape and position of the microstructures define their functionality. Typical structure heights for diffractive structures used in the visible spectrum are in the micrometer range, while the lateral dimensions of the individual microstructures can range from the order of the design wavelength or below up to several millimeters. Typical structure shapes are binary elements with only two levels in the structures, multilevel elements or quasi-continuous, saw-tooth like structures. Laser direct writingLaser direct writing of such structures has proven to be a flexible, fast and cost-effective approach. Depending on the application and process, the fabricated structures are used directly in the application or form the master shape for a subsequent replication process. Figure 1 gives a principle overview. There are processes that use laser direct writing to directly structure the surface (e.g., via ablation or thermal processes) or modify optical properties like the refractive index to obtain a diffractive optical element directly, but more common are photoresist based processes known from lithography as used in semiconductor manufacturing. Here, a photo sensitive layer, the photoresist layer, is coated onto a substrate. The thickness of the layer depends on the required structure depth and the subsequent process; typical values are a few hundred nanometers to a few micrometers. The photoresist changes its solubility depending on the energy that is absorbed by the writing laser. This allows in the subsequent developing step to obtain a photoresist profile from the light pattern that was written into the layer. The photoresist profile can be used directly as diffractive element for wavelengths

show abstract

Laser direct writing of rotationally symmetric high-resolution structures

Cited by 15 publications

References 22 publications

Large dynamic range Shack–Hartmann wavefront sensor based on holographic multipoint generation and pattern correlation

Large dynamic range Shack–Hartmann wavefront sensor based on holographic multipoint generation and pattern correlation

Recent developments and challenges of nanopositioning and nanomeasuring technology

Laser direct writing

Contact Info

Product

Resources

About