Acousto-optic Device Chromatic Spread Angle Correction
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Solution Overview
Problem
In multiphoton microscopy, the chromatic spread angle (CSA) caused by acousto-optic elements leads to non-collinear propagation of different color components, resulting in reduced resolution and efficiency due to elliptical beam profiles and spatial separation of light components, which existing solutions either fail to address effectively or are costly and inflexible.
Innovation Solution
An apparatus comprising an acousto-optic element and two focusing optical units, where the first unit is placed upstream to focus the incident light beam and the second unit is placed downstream to ensure collinearity of diffracted chromatic components, effectively reducing the chromatic spread angle and maintaining high-quality imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an acousto-optic element is used to modulate light wavelength, then wavelength selectivity and modulation speed are improved, but chromatic spread angle increases causing non-collinear propagation of different color components
Solution Approach 1:
A relay optical system with two lenses is introduced as an intermediary between the acousto-optic element and the objective lens. The first lens focuses the diffracted light to a point in the object plane, and the second lens recollimates the light beams. This relay system acts as a mediator that corrects the chromatic spread angle while preserving the wavelength modulation capability of the acousto-optic element.
Solution Approach 2:
The invention changes the optical parameters of the beam path by introducing focusing optical units that modify the wavefront curvature and propagation direction. By adjusting the focal lengths and positions of the relay lenses, the system compensates for the chromatic dispersion introduced by the acousto-optic element, restoring collinearity without affecting the modulation function.
2Manufacturing precision
If chromatic spread angle is reduced to improve resolution, then beam collinearity is improved, but existing solutions are costly and inflexible
Solution Approach 1:
The relay optical system serves multiple functions simultaneously: it focuses the incident light beam, corrects chromatic spread angle, maintains beam collinearity, and preserves wavelength modulation capability. By making the optical system multi-functional, the invention avoids the need for separate complex correction systems, reducing overall device complexity while achieving high precision.
3Measurement precision
If focusing optical units are added to reduce chromatic spread angle, then resolution and peak intensity are improved, but device complexity increases
Solution Approach 1:
The invention merges the functions of the relay optical system with the existing beam path components. The two lenses are integrated into the conventional optical architecture of the microscope, combining the correction function with the existing imaging path. This merging approach minimizes additional complexity while achieving the desired resolution improvement through maintained beam collinearity.
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
The solution provides a cost-effective and flexible method to significantly reduce the chromatic spread angle, ensuring high-quality multiphoton microscopy by maintaining collinearity of chromatic components at the objective lens pupil and improving peak intensity and resolution.
Implementation Method 1
use can be made of wavelength-selective elements which are based on the acousto-optic effect. As a rule, such acousto-optic elements have a so-called acousto-optic crystal which is made to vibrate by means of an acoustic transducer. By applying radio frequencies to the electrodes, said radio frequencies typically lying in the range between 10 MHz and 10 GHz, the piezoelectric material is excited to vibrate such that an acoustic wave that passes through the crystal can arise. Acousto-optic crystals are distinguished in that the soundwave arising changes the optical properties of the crystal. In particular, a periodic modulation of the local refractive index is achieved. This modulation acts like a (Bragg) grating and can diffract light of an appropriate wavelength.
Implementation Method 2
such a transducer has a piezoelectric material and two or more electrodes contacting this material. By applying radio frequencies to the electrodes, said radio frequencies typically lying in the range between 10 MHz and 10 GHz, the piezoelectric material is excited to vibrate such that an acoustic wave that passes through the crystal can arise.
Implementation Method 3
the first focusing optical unit is disposed in the beam path upstream of the acousto-optic element and the second focusing optical unit is disposed in the diffracted light such that a focus of the incident light beam is situated downstream of the first focusing optical unit in the acousto-optic element
Implementation Method 4
the virtual interaction point is located in a front focus of the second focusing optical unit
Data Source
AI summary
An apparatus for reducing a chromatic spread angle of light diffracted at an acousto-optic element includes the acousto-optic element and a first and a second focusing optical unit. The acousto-optic element is disposed in a beam path of an incident light beam and is configured to generate the diffracted light from the incident light beam such that the diffracted light emanates from a virtual interaction point of the acousto-optic element. The first focusing optical unit is disposed in the beam path upstream of the acousto-optic element and the second focusing optical unit is disposed in the diffracted light such that a focus of the incident light beam is situated downstream of the first focusing optical unit in the acousto-optic element and the virtual interaction point is located in a front focus of the second focusing optical unit.