Custom Optical Scanning
& Autofocus Systems
Engineered for Your Application
OFH designs and builds custom voice-coil driven optical systems: closed-loop autofocusing heads for laser processing, resonant mirror scanners for OCT, and 2D beam deflectors for imaging and metrology. Complete integrated systems or individual subsystems.
- Voice-Coil Actuators
- Autofocus Systems
- 2D Beam Scanners
±2.5 µm
Demonstrated focus accuracy
380 Hz
Resonant mirror scanner (OCT)
1.2 kHz
Closed-loop servo bandwidth
2D
Angular scanning (dual-axis)
0.61 NA
High-NA writing lens
We've Built These. We Can Build Yours.
Two distinct systems, one for precision laser processing, one for OCT beam scanning.
Both built on the same core expertise: voice-coil actuation, leaf-spring suspension, and custom opto-mechanical integration.
Laser Processing
Closed-Loop Autofocusing Optical Head
Complete optomechatronic system for sub-micron focal tracking on moving, non-planar surfaces. Integrated voice-coil actuator, beryllium-copper leaf-spring suspension, off-axis AF sensor with dual-element segmented photodiode, beam-shaping optics, and digital PID servo — in a single cleanroom-ready block.
OCT / Biomedical Imaging
Resonant Mirror Actuator for OCT Beam Scanning
Custom voice-coil driven mirror actuator for an OCT portable system, delivering sinusoidal beam deflection at a tunable resonant frequency. Designed for optical path modulation with a partial mirror in the reference arm. Beryllium-copper leaf springs with adjustable working length for frequency tuning. Built and qualified by OFH before delivery.
Complete Systems or Any Subsystem in Isolation
Every engagement is scoped to what you need. Some clients come to us for an integrated system. Others need a single subsystem — a specific actuator, a custom suspension, or a 2D scanner — to plug into their existing platform.
Complete System
Integrated Autofocusing Optical Head
Full closed-loop system in a single block: VCM actuator, suspension, AF optical sensor, beam-shaping optics, and digital servo controller. Configurable for your wavelength, NA, bandwidth, and envelope.
Complete System
Resonant Mirror Scanner for OCT
Voice-coil driven mirror actuator operating at resonance for low-power, high-stability sinusoidal beam scanning. Used in OCT reference arms, interferometry, and swept-source imaging. Resonant frequency set by leaf-spring geometry and tunable at assembly.
Subsystem
Voice-Coil Actuator (VCM)
Single-axis electromagnetic drive for fast, precise linear or angular positioning of rather heavy moving objects. Used wherever you need high-bandwidth force control without stiction, backlash, or wear. Can be configured for resonant or non-resonant operation depending on application.
Subsystem
Leaf-Spring Flexure Suspension
Parallelogram beryllium-copper leaf-spring suspension for frictionless, repeatable linear guidance. No lubrication, no wear, no stiction. Own suspension frequency spectrum is set by spring mechanical design — tunable at assembly for prototype flexibility.
Subsystem
Autofocus Sensor & Servo Controller
Off-axis focus error detection using a segmented photodiode (quadrant or dual-element), generating sum and differential signals for S-curve based focus error discrimination. Paired with a digital PID servo controller driving the VCM.
Subsystem
2D Angular Beam Scanner
Dual-axis mirror scanner for 2D beam deflection over a target field. OFH has designed and modeled 2D VCM scanners for OCT systems with scan fields up to 16 × 12 mm. Can be paired with F-theta or telecentric scan lenses for flat-field imaging.
How These Systems Work
If you're evaluating whether OFH can solve your problem, these are the underlying technologies we work in.
Voice-Coil Actuator
Electromagnetic Linear & Angular Drive
A voice-coil actuator (VCM) generates force by passing current through a coil in a static magnetic field produced by high effective NdFeB and SmCo magnets. Special dampers provide the flatter-free movement. No gears, no screws, no contact — just smooth, bidirectional force proportional to current. This makes VCMs ideal for high-frequency, high-precision motion where friction or backlash would introduce error. OFH designs both the magnetic circuit and the coil geometry for your force, stroke, and bandwidth target.
Leaf-Spring Suspension
Flexure-Based Frictionless Guidance
A parallelogram leaf-spring suspension guides the moving part of an actuator with zero friction and zero wear. The resonant frequency is determined by spring stiffness and moving mass — OFH models and tunes this to match your operating frequency. Beryllium-copper springs offer the best fatigue life and stiffness-to-mass ratio for optical actuator applications. Spring working length is tunable at assembly for prototype flexibility.
Segmented Photodiode AF
Quadrant & Dual-Element Focus Error Detection
Autofocus systems use a segmented photodiode — quadrant (four-quadrant) or dual-element — to detect the focus error signal. An off-axis probe beam is reflected from the target surface; its position on the detector shifts with defocus, generating an S-curve error signal. The sum signal (A+B) gives intensity; the differential signal (A−B) gives focus error. OFH designs both the optics and the signal processing electronics.
Resonant vs. Non-Resonant
Choosing the Right Operating Mode
A resonant actuator runs at its mechanical resonant frequency — 10× lower power consumption, frequency stability defined by the spring-mass system, not electronics. A non-resonant actuator runs off-resonance — simpler design, easier manufacturing tolerances, but requires tighter electronic drive stability and more power. OFH has built both and can help you choose based on your power budget, frequency stability requirement, and system complexity tolerance.
F-Theta & Scan Lenses
Flat-Field Beam Scanning Optics
A galvo or VCM scanner deflects a beam angularly, but without a scan lens, the focused spot traces a curved arc — not a flat field. F-theta lenses convert angular deflection to linear scan position, providing a flat image field and constant spot velocity. For OCT and confocal applications, telecentric scan lenses (like the Thorlabs LSM series) maintain constant beam angle at the sample. OFH models the full scan system in Zemax, including scan lens, field curvature, and spot size across the field.
Closed-Loop Servo
Digital PID Control for Optical Actuators
A closed-loop servo reads the position or focus error from a sensor, computes a correction via a PID (proportional-integral-derivative) controller, and drives the VCM coil current to minimize error. The digital PID controller provides the easy adaptability of servo system to your specific tracking system. The servo bandwidth — how fast the loop can respond — is limited by the actuator’s mechanical resonances. OFH designs the full control loop: sensor, signal conditioning, digital PID implementation, and VCM driver, matched to your required tracking accuracy and surface dynamics.
Resonant vs. Non-Resonant Actuator Operation
One of the first questions in any OCT scanner or mirror actuator design. Both approaches are feasible. The
right choice depends on your power budget, frequency stability requirements, and system complexity tolerance.
Custom Optical Scanning & Autofocus Systems FAQ
Can OFH build a complete system, or just the subsystem I need?
Optics for Hire provides full-service custom lens design and optical engineering — from initial concept through Zemax modeling, tolerance analysis, prototyping, and production support. We design custom lenses optimized for your specific performance requirements including wavelength range, field of view, resolution, and packaging constraints.
Should my scanner run in resonant or non-resonant mode?
Our optical engineers design a wide range of custom lens systems including microscope objectives, zoom lenses, endoscopes, ophthalmoscopes, barcode readers, distance measurement optics, night vision systems, IR systems, confocal imaging lenses, MEMS device lenses, motion capture optics, 3D display optics, illumination systems, reflectors, collimators, and laser marking systems. We work with both imaging and non-imaging optical designs.
What performance has OFH actually demonstrated?
Our custom lens design process includes four stages: (1) Optical Design — custom lens designs optimized for your performance requirements; (2) Zemax Modeling — detailed optical simulations, ray-tracing analysis, tolerance analysis, and stray light modeling; (3) Opto-Mechanical Design — developing assemblies that minimize the impact of manufacturing tolerances on optical performance; (4) Prototyping and Testing — validating that performance matches design expectations with in-house testing and trusted manufacturing partners.
Which parameters can be customized?
We provide custom lens design and optical engineering consulting to companies of every size — from university research labs and early-stage startups to Fortune 500 corporations. Whether you need a single custom lens design, a feasibility study, or a full optical engineering program from design through production, our team scales to your project requirements.
What applications are these systems used for?
Yes. Prototyping is an integral part of our custom lens design process. We manage prototype fabrication through trusted optical manufacturing partners and verify results with in-house testing. This lets you validate that your custom lens meets its optical performance specifications — including MTF, resolution, and distortion targets — before committing to volume production.
Do you model the system before building it?
Yes. Our custom lens design service extends through volume production. Once your optical design is validated through prototyping and testing, we provide full production-ready documentation, manage the transition to manufacturing, and support your production run to ensure consistent quality and optical performance at scale.
Why voice-coil actuation instead of gears or screws?
Project timelines vary depending on complexity. A straightforward singlet or doublet lens design can be completed in a few weeks, while complex multi-element zoom lens systems or systems requiring custom Zemax DLLs may take several months. We provide a timeline estimate during our initial consultation after reviewing your optical specifications and performance requirements.