Multi-Pass Deformable Mirror Control for Axial Laser Focus
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Solution Overview
Problem
Current devices for controlling the axial position of a laser focal point in microscopy are limited by the small surface deflection and high settling times of deformable mirrors, restricting the working space and scanning frequency, which hampers applications like confocal microscopy and optical manipulation.
Innovation Solution
The device passes the laser beam multiple times through a deformable mirror, amplifying focalization or defocalization, increasing the axial position control and reducing settling times, while maintaining optical efficiency through the use of virtual deformable mirrors and optical relay systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a deformable mirror is used to control axial position of laser focal point, then focal point position control is achieved, but the working space is limited due to small surface deflection
Solution Approach 1:
The patent combines multiple passes of the laser beam through the same deformable mirror to accumulate the optical effect. By reflecting the beam multiple times off the deformable mirror surface, the small surface deflection is multiplied, effectively enlarging the working space without requiring a larger physical mirror deflection capability.
Solution Approach 2:
The laser beam continuously interacts with the deformable mirror through multiple reflections rather than a single pass. This continuous interaction amplifies the effect of the mirror's surface deflection, allowing the system to achieve larger axial position control range from a mirror with limited surface deflection capability.
2Productivity
If a deformable mirror is used to control axial position of laser focal point, then focal point position control is achieved, but scanning frequency is limited due to high settling times
Solution Approach 1:
Multiple beam passes through the deformable mirror are combined within a single settling cycle. The optical path is configured so that the beam reflects off the mirror multiple times before reaching the focal point, effectively multiplying the mirror's action without requiring multiple settling cycles, thus increasing scanning frequency.
Solution Approach 2:
The system maintains continuous useful action by keeping the laser beam in constant interaction with the deformable mirror through multiple reflections. This allows the mirror to achieve its settled position once and produce amplified effects throughout the multiple beam passes, rather than requiring repeated settling for each position adjustment.
3Volume of moving object
If laser beam is passed multiple times through deformable mirror, then workspace is enlarged, but device complexity increases
Solution Approach 1:
The same deformable mirror performs multiple functions by serving as the sole optical element for multiple beam passes. Rather than introducing additional mirrors or complex mechanisms, the system uses the existing deformable mirror repeatedly, simplifying the overall device architecture while achieving enlarged working space.
Solution Approach 2:
Fixed mirrors are introduced as intermediaries to redirect the laser beam back to the deformable mirror multiple times. These intermediary elements are stationary and require no active control, allowing the beam to traverse the deformable mirror's surface multiple times while adding minimal complexity to the system.
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 approach significantly enlarges the actuation axis workspace and increases scanning frequency, enabling high-speed motion control of the laser focal point over a larger working space, thus enhancing applications such as 3D scanning and optical manipulation.
Implementation Method 1
a deformable mirror for focusing or defocusing the laser beam axially
Implementation Method 2
They contain an array of actuators allowing a parabolic deflection of their surface, changing the mirror focal length
Data Source
AI summary
The present invention relates to a device (IO) for controlling the axial position of a laser focal point produced by a microscope objective, comprising: —a laser source for emitting a laser beam, —a deformable mirror for focusing or defocusing the laser beam axially, —a microscope objective for focusing the laser beam coming from the deformable mirror on a laser focal point, characterized in that it further comprises a system for passing the laser beam emitted by the laser source several times through the deformable mirror.