The HIS180SMD-S functions as a pulsable thermal infrared source. When electrical power is applied to the micro-fabricated resistive element, it heats rapidly and radiates energy across a broad infrared spectrum governed by Planck’s law. At its nominal operating temperature of ~550 °C, the emission peak falls in the mid-infrared, providing strong coverage across the molecular fingerprint region.

The nanostructured surface coating on the radiating element achieves emissivity greater than 0.9, closely matching ideal blackbody behaviour. This maximises the conversion of electrical power into radiant flux and ensures a spectrally smooth output that is predictable for filter-based system design.

In NDIR gas detection, the emitter’s output passes through a sample cell containing the gas under analysis. Molecular species present absorb radiation at their characteristic vibrational absorption wavelengths; a matched photodetector and narrow bandpass filter measure the transmitted intensity to quantify concentration. Pulsed operation — supported up to 8 Hz — enables lock-in detection, effectively rejecting broadband thermal background and 1/f noise to improve both sensitivity and long-term baseline stability.

Wide 2–14 µm Spectral Range

The HIS180SMD-S covers the entire mid-infrared and extends into the long-wave infrared band, providing access to the fundamental absorption features of CO₂, CO, CH₄, N₂O, SO₂, NH₃, many hydrocarbons, and complex organic molecules. This broad coverage makes a single emitter suitable for multi-analyte detection platforms and eliminates the need for multiple source types in wideband instruments.

Industry-Leading Optical Output Power

With up to 35 mW of optical output, the HIS180SMD-S delivers the highest radiant power among emitters in this package class. Higher flux at the source directly increases the signal-to-noise ratio at the detector, enabling either longer optical path lengths, lower detection limits, or both simultaneously.

Si-ARC Window for Broadband Transmission

The silicon substrate of the optical window is inherently transparent across the 1.2–14 µm range. The applied anti-reflection coating suppresses surface reflections at the air–silicon interfaces, maximising transmitted power and reducing etalon artefacts. The Si-ARC window also provides robust protection against particulates, condensation, and chemical vapours in industrial environments.

Large 1.8 mm² Radiating Element

A larger emitting area generates greater total radiant flux at any given operating temperature. The 1.8 mm² element of the HIS180SMD-S produces substantially more output than the smaller elements found in competing miniature emitters, enabling more sensitive detection or relaxed optical alignment tolerances in sensor system design.

Patented Nanostructured High-Emissivity Surface

The patented nanostructure process creates a surface with emissivity exceeding 0.9 — close to the theoretical maximum for a blackbody. This ensures maximum radiant efficiency and a spectrally predictable output, simplifying calibration and filter selection in sensor designs.

Pulsed Operation up to 8 Hz

Modulated emission enables synchronous detection in downstream signal processing circuits. Lock-in techniques referenced to the modulation frequency effectively reject DC thermal background, reducing measurement uncertainty and extending long-term calibration stability in field-deployed instruments.

SMD Package for Volume Manufacturing

The 3 × 3 mm footprint and SMD terminations are fully compatible with standard reflow soldering and pick-and-place assembly. This removes handling complexity from the manufacturing process and enables high-volume, cost-effective production of gas sensor PCB assemblies.

• hydrocarbons, and other infrared-absorbing gases in industrial, environmental, and indoor air quality systems.
• Long-Wave Infrared Spectroscopy: Portable and benchtop spectrometers targeting molecular fingerprint features beyond 6 µm for material identification, pharmaceutical QC, food analysis, and chemical detection.
• Environmental and Emissions Monitoring: Continuous emissions monitoring systems (CEMS), greenhouse gas analysers, and ambient air quality networks requiring broad spectral coverage.
• Industrial Safety and Hazardous Gas Detection: Fixed and portable detectors in petrochemical plants, refineries, wastewater treatment facilities, and confined-space safety equipment.
• Smart Buildings and HVAC: Indoor air quality sensors monitoring CO₂, VOCs, and other gases for demand-controlled ventilation and occupancy-based climate management.
• Medical and Clinical Diagnostics: Capnography, anaesthetic gas monitoring, respiratory analysis, and breath alcohol detection instruments.
• Consumer and IoT Devices: Smart home air quality monitors, wearable environmental sensors, and connected industrial IoT nodes requiring wideband infrared coverage.

United Spectrum Instruments (USI) is a specialist distributor and application partner for advanced photonics, infrared sensing, and scientific instrumentation in India. By combining access to globally leading component technologies with deep domain expertise, USI supports OEM developers, research institutions, and system integrators throughout the product development cycle — from initial component selection to production ramp.

Key reasons to work with United Spectrum Instruments:

• Access to internationally leading infrared and photonics component technologies
• Expert application support for NDIR gas sensing, spectroscopy, and IR system design
• OEM consultation from prototype through to volume production
• Reliable supply for evaluation samples and production quantities
• Established partnerships with leading international photonics manufacturers
• Fast, responsive technical communication and application guidance