LQS — LASER Cutaneous Stimulator

Class 1C LASER stimulation for LASER-evoked potential research

The LQS — LASER Cutaneous Stimulator is a research instrument developed by QST.Lab for controlled cutaneous thermal stimulation in LASER-evoked potential (LEP), nociception, thermoception, and pain research protocols.

Designed as a Class 1C LASER stimulator, the LQS combines the benefits of LASER-based thermal stimulation with an integrated safety architecture adapted to controlled skin-contact applications.

It provides researchers with a compact, reproducible, and protocol-driven solution for delivering localized thermal stimuli while supporting precise synchronization with electrophysiology acquisition systems.

Optimized for LASER-evoked potentials

The LQS is particularly suited for laboratories working with electroencephalography (EEG) and evoked potential recordings.

A dedicated 0–5 V TTL (Transistor-Transistor Logic) trigger output allows each stimulation to be precisely synchronized with external acquisition systems. This enables accurate temporal alignment between the cutaneous stimulus and the recorded electrophysiological response.

The LQS is therefore well adapted to protocols involving:

LASER-evoked potentials (LEPs)
Nociceptive pathway assessment
Thermo-nociceptive stimulation
Pain research
Somatosensory research
Controlled cutaneous thermal stimulation

LEPs showing the difference in N2P2 wave amplitude for 1, 4, and 8 LEDs

1470 nm LASER LEDs for targeted cutaneous stimulation

The LQS uses 1470 nm LASER LEDs, a wavelength selected for controlled cutaneous thermal stimulation.

At this wavelength, optical energy is strongly absorbed in superficial skin layers. This allows the stimulus to be delivered close to cutaneous sensory fibers while limiting excessive energy penetration into deeper tissues.

This stimulation approach is particularly relevant for activating thermo-nociceptive pathways and recording LASER-evoked potentials.

Advantages of 1470 nm stimulation

Superficial and controlled energy deposition
Stimulation close to cutaneous sensory fibers
Fast and localized thermal stimulation
Reduced risk of deep tissue heating
Improved repeatability between stimulations
Reduced risk of skin burns when used within the device’s safety limits
Suitable integration into electrophysiology and pain research protocols

Alternative wavelengths may also be proposed on request, depending on the scientific protocol and target tissue interaction required.

Why Class 1C matters

The Class 1C classification is especially relevant for laboratories using LASER stimulation on the skin.

It allows controlled optical energy to be delivered to the target tissue while integrating safety mechanisms that limit exposure conditions and reduce operational risks.

For research teams, this provides several practical advantages:

Safer use in experimental workflows compared with open-beam LASER configurations
Controlled skin-contact stimulation
Reduced need for complex LASER-room constraints, depending on local safety rules and institutional procedures
Improved usability for repeated experimental sessions
Easier integration into neurophysiology laboratories
A compact and practical alternative to traditional high-class LASER stimulation systems

Controlled and reproducible thermal stimulation

The LQS stimulation probe includes eight independent 1470 nm LASER LEDs, allowing flexible stimulation configurations and precise control of the stimulated area.

Users can define stimulation parameters directly from the touchscreen interface or through USB/serial computer control.

Main stimulation features

8 independent 1470 nm LASER LEDs
Beam surface:
- 1 LED: 0.21 cm²
- 8 LEDs: 1.70 cm²
Adjustable stimulation duration
Adjustable energy density
Selection of active diodes
Infrared skin temperature monitoring
Touchscreen interface
Custom protocol creation
USB/serial control for automated experiments
0–5 V TTL trigger input/output
CSV data recording and export
Autonomous battery operation
Optional alternative wavelengths on request

Integrated safety architecture

The LQS includes built-in safety functions designed to support controlled laboratory use.

Safety features include

Startup self-test of the LASER LEDs
Power-density and stimulation-duration limitation
Real-time energy monitoring
Automatic stimulation interruption
Galvanic insulation
Skin-contact detection

These functions help researchers deliver repeatable stimuli while maintaining controlled exposure conditions during experimental sessions.

Flexible protocol-based operation

The LQS allows users to create and execute custom experimental protocols directly from the device.

Protocol steps can include:

Stimulation events
Waiting periods
Trigger input or output
Response-button events
Repetitions
Data recording

Recorded data are stored in CSV format and can be exported via USB for further analysis.

Key benefits

Designed for LASER-evoked potential research
Class 1C LASER architecture for controlled skin-contact use
1470 nm wavelength for superficial cutaneous stimulation
Eight independent LASER LEDs for flexible stimulation areas
TTL synchronization with EEG and external acquisition systems
Protocol-based operation for reproducible experimental workflows
Integrated safety functions
Compact, practical, and suitable for repeated laboratory use