TopMode

• Single-frequency CW operation for highly coherent laser output.
• Narrow linewidth <5 MHz for high spectral purity.
• Coherence length >25 m, making it suitable for interferometric and holographic applications.
• CHARM active coherence stabilization continuously monitors and maintains single-frequency operation.
• Wavelength stability <1 pm/h (typically <0.5 pm/h peak-to-peak).
• Available wavelengths from approximately 375 to 515 nm with customized wavelength options.
• Up to 100 mW optical output at 405 nm in the high-power version.
• Built-in optical isolation >30 dB to reduce sensitivity to optical feedback.
• Compact and passively air-cooled laser head for low-vibration operation.
• Designed with OEM integration in mind.
• Optional SmartDock fiber coupling with a typical coupling efficiency of approximately 50% into single-mode fiber.
• Optional tighter wavelength specification of ±0.25 nm.
• Python Laser SDK support for computer-based laser control.

The TOPTICA TopMode is a single-frequency, narrow-linewidth diode laser designed for applications requiring high optical coherence, excellent wavelength stability, and reliable long-term single-frequency operation.

Unlike conventional diode lasers, the TopMode uses an external-cavity architecture combined with TOPTICA's proprietary CHARM coherence-control technology. CHARM actively monitors the laser and maintains single-frequency operation, helping the laser remain stable during extended operation and changing environmental conditions.

The TopMode provides a spectral linewidth below 5 MHz and a coherence length greater than 25 m. These characteristics make it particularly attractive for applications where phase coherence and spectral purity directly affect measurement accuracy, including interferometry, holography, Raman spectroscopy, and precision metrology.

The 405 nm version is a particularly strong configuration, offering up to 100 mW of optical power while maintaining single-frequency operation. The 405 nm wavelength is also visible to the human eye and can be efficiently detected using silicon-based detectors, making it convenient for optical alignment and measurement systems.

The TopMode is available in a range of wavelengths from 375 to 515 nm, with customized wavelength options available through the TopMode CD variant. A tighter wavelength specification of ±0.25 nm can also be requested instead of the standard ±2 nm specification.

For systems requiring fiber delivery, the optional FD2 configuration incorporates TOPTICA's SmartDock fiber coupler and a polarization-maintaining fiber. An additional optical isolator can also be specified when greater protection from optical feedback is required.

The compact, passively cooled laser head is designed for OEM integration, making the TopMode suitable not only as a laboratory laser source but also as a component within analytical instruments, metrology systems, imaging systems, and industrial optical equipment.

Product Type: Single-Frequency, Narrow-Linewidth Diode Laser
Model: TopMode
Operation: CW, Single (Fixed) Frequency
Wavelength Range: 375–515 nm*
Typical Model: TopMode 405
Wavelength: 405 ± 2 nm
Wavelength Selection: ±0.25 nm upon request
Wavelength Tuning: No
Wavelength Stability: <1 pm/h (<0.5 pm/h typ.), peak-to-peak
Linewidth: <5 MHz (<0.01 pm)
Coherence Length: >25 m
ASE Suppression: 40 dB typ.
Optical Power, Free Space: 50 mW / up to 100 mW with HP option
Optical Power, Fiber-Coupled: 25 mW / up to 50 mW with HP option
CHARM: Active Coherence Stabilization
Power Stability: Typ. <0.5% (STD/mean)/h
Intensity Noise: ≤0.1% RMS at 10 Hz–10 MHz
Polarization: Linear, >100:1
Beam Shape: Collimated, Circular
Beam Diameter: Typ. 1 mm FWHM / 1.7 mm (1/e²)
Beam Ellipticity: <10%
Beam Quality: M² < 1.5 (< 1.2 typ.)
Optical Isolation: Built-in, >30 dB
Fiber Coupling: Optional, typically 50% into SM fiber
Cooling: Passive Laser Head Cooling
Laser Class: Class 3B
Communication: Ethernet, USB
Operating Temperature: 15–30°C
Power Consumption: Typ. <70 W, max. 150 W

The TopMode is particularly suitable for applications where high coherence, narrow linewidth, and wavelength stability are critical.

Raman Spectroscopy
Raman Microscopy
Inorganic Material Analysis
Material Characterization

The 405 nm wavelength can be particularly useful for Raman measurements where strong excitation and compatibility with silicon detectors are advantageous.

Precision Metrology
Optical Metrology

• Interferometry
• Semiconductor Inspection
• Dimensional Measurement
• Surface Measurement
• Layer Thickness Measurement

The long coherence length and high wavelength stability make the TopMode suitable for precision interferometric measurements.

Holography & Imaging

• Digital Holography
• Holographic Imaging
• Holographic Data Storage
• Augmented Reality (AR)
• Optical Imaging

The combination of single-frequency operation and long coherence length is particularly beneficial for holographic applications.

Lithography & Semiconductor

• Direct-Writing Lithography
• Laser-Based Patterning
• Semiconductor Inspection
• Wafer Metrology
• Optical Inspection

TOPTICA specifically identifies direct-writing lithography and semiconductor inspection/metrology as TopMode applications.

Other Applications

• Optical Instrumentation
• Precision Laser Systems
• Coherent Imaging
• Scientific Research
• Photonics Research
• OEM Optical Systems
• Interferometric Sensors
• Quantum Optics