Compact Polarizing Optical Separator for Stellar Interferometry

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Solution Overview

Problem

Existing polarizing beam splitters for stellar intensity interferometry in atmospheric Cherenkov detectors are not compact, and their polarizing ability is dependent on the angle of incidence, which affects the accuracy of signal evaluation due to differing optical paths and inability to change light polarization combinations.

Innovation Solution

A monolithic and compact polarizing optical separator design with a narrowband optical filter and a beam splitter system where the optical path remains constant, allowing for precise timing of light arrival and adjustable polarization combinations, ensuring identical propagation directions and independence from angle of incidence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If conventional polarizing beam splitters are used, then beam splitting function is achieved, but the device size is large and not compact

Engineering Contradiction:
Improvedevice sizeVSAvoidoptical setup complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent combines multiple optical components (beam splitter, polarizers, wave plates, mirrors) into a single integrated optical separator unit. This merging of components achieves the desired compactness while maintaining all necessary optical functions for stellar intensity interferometry.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The optical separator is designed to perform multiple functions simultaneously: beam splitting, polarization control, and optical path length equalization. This multi-functionality reduces the need for separate devices, achieving compactness without sacrificing capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If conventional polarizing beam splitters are used, then beam splitting is achieved, but the polarizing ability depends on angle of incidence

Engineering Contradiction:
Improvesignal evaluation accuracyVSAvoidangle of incidence dependence
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent employs wave plates to actively control and adjust the polarization state of light beams. By changing the orientation and type of wave plates, the system can compensate for angle of incidence variations and maintain accurate polarization-dependent signal evaluation across different operating conditions.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical alignment sensitivity of conventional beam splitters with an optical control system using wave plates and polarizers. This substitution allows electronic/optical adjustment of polarization states rather than relying on precise mechanical angular alignment.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If different optical paths are used for split beams, then flexibility in optical design is achieved, but timing precision of photon detection deteriorates

Engineering Contradiction:
Improvephoton correlation timing precisionVSAvoidoptical path configuration
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical separator is designed with equal optical path lengths for both split beams. This equipotential design ensures that photons from the same source event arrive at detectors simultaneously, maximizing timing precision for photon correlation measurements without requiring complex synchronization electronics.

Inventive Principle:
Principle #12Equipotentiality

Solution Approach 2:

The patent introduces selective optical elements (wave plates, polarizers) at specific locations in each optical path to provide local polarization control. This allows differential manipulation of the two beams while maintaining equal overall path lengths, achieving both timing precision and polarization versatility.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design enhances signal processing accuracy by ensuring identical optical paths for both split beams, allowing for precise detection of photon correlations with improved precision in tens of picoseconds, enabling more accurate evaluation of stellar intensity interferometry data.

Implementation Method 1

a beam splitter (21) dividing an incident beam into two beams (Sd1, Sd2) with identical directions of propagation and with equal optical path lengths

Methodology Applied
Scientific EffectBeam splitting:

Implementation Method 2

both beams (Sd1, Sd2) being polarized in polarizers (25, 32)

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 3

A monolithic and compact polarizing optical separator design with a narrowband optical filter

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 4

followed, in the direction of the output of the first split beam Sd1, by the secondary mirror prism 24

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4042213B1Polarizing optical separator for stellar intensity interferometry
Publication Date: 2025.01.15 UNIV PALACKEHO V OLOMOUCI
  • EP4042213B1 patent drawingFigure 1

AI summary

A polarizing optical separator for stellar intensity interferometry, particularly for use in atmospheric Cherenkov detector, where the separator consists of a fixed optical setup (2) and a rotaiy optical setup (3), where the fixed optical setup (2) is formed by a beam splitter (21) to which a primary mirror prism (22) is attached in the direction of an incidental input beam (Sin) and a deflecting mirror prism (23) is attached in the direction perpendicular to the input beam (Sin), where the primary mirror prism (22) is followed by a secondary mirror prism (24) fitted with the first polarizer (25) on the output surface, and where the rotatable optical setup (3) is formed by a transitive prism (31) provided with the other polarizer (32) on an output surface and is rotatably attached to the deflecting mirror prism (23). The fixed optical setup (2) and the rotatable optical setup (3) are provided with detectors (4) and moreover they are selected so that the optical paths of the split output beams (Sd1) and (Sd2) in both separator arms are essentially identical.