The HIS2000R-C300-6 operates as a resistive thermal emitter. Electrical current through the 40 mm² NiCr filament raises its temperature to approximately 630 °C; the nanostructured surface (emissivity >0.9) radiates energy across a broad Planck-governed spectrum. The gold-plated reflector captures rear-hemisphere radiation and redirects it forward, recovering energy that would otherwise be absorbed by the TO-8 package walls. The resulting beam passes through the CaF₂ window, which transmits efficiently from ~0.13 µm to ~11 µm.

Calcium fluoride is a cubic fluorite-structure crystal whose long-wave transmission cut-off near 11 µm is determined by multi-phonon lattice absorption. Its transmission within the 2–11 µm band is high and spectrally smooth, providing a predictable source spectrum for filter-based gas detection systems. Compared to BaF₂ (cut-off ~14 µm), CaF₂ sacrifices the longest-wavelength mid-IR coverage while offering meaningfully better mechanical properties: greater hardness (Mohs ~4 vs. ~3) and substantially lower hygroscopicity. At the drive power levels of the HIS2000R-C300-6, these material properties are relevant to long-term window integrity under the thermal cycling experienced during continuous operation.

The nitrogen fill displaces reactive species from the package interior, eliminating internal oxidation and corrosion. Pulsed modulation at up to 4 Hz supports synchronous lock-in detection in NDIR instruments, rejecting thermal background and 1/f noise to improve signal-to-noise ratio and long-term baseline stability.

CaF₂ Window: Extended Mid-IR Coverage to 11 µm with Practical Durability

Calcium fluoride transmits from ~0.13 µm to ~11 µm, extending the usable spectral range of the sealed TO-8 family by nearly two octaves beyond the 6 µm sapphire cut-off. This coverage encompasses the fundamental mid-infrared absorption features of SO₂ (~7.3 µm and ~8.7 µm), NH₃ (~8.5–11 µm), N₂O (~7.8 µm), and many C–H, C–O, and C–N bending and stretching modes of organic compounds in the 6–11 µm fingerprint region. CaF₂’s Mohs ~4 hardness and low hygroscopicity make it significantly more durable in practical instrument environments than the BaF₂ used in the wider-range HIS550R-B, particularly under the thermal cycling conditions of continuous industrial operation.

780 mW Optical Output Across 2–11 µm

At 780 mW, the HIS2000R-C300-6 delivers more than four times the optical output of the hermetically sealed HIS550R-C (190 mW, TO-39, same CaF₂ window), and more than five times that of the HIS550R-A (135 mW, sapphire). This large signal budget directly supports the long optical path lengths needed for trace-gas detection, instruments with high insertion loss optical trains, and multi-analyte analysers simultaneously targeting multiple absorption bands across the 2–11 µm range.

Hermetic Sealing and Nitrogen Fill

The hermetic TO-8 package combined with nitrogen fill eliminates internal oxygen and moisture — the two primary causes of NiCr filament degradation at operating temperature. This is particularly important for the CaF₂ window: the nitrogen fill protects the inner window surface from moisture exposure that would etch CaF₂ and progressively degrade transmission. The external window face is protected by the instrument enclosure in normal use; the internal face is protected throughout the device’s service life by the hermetic seal and nitrogen atmosphere.

Large 40 mm² Element with Gold-Plated Reflector

The 40 mm² NiCr filament generates total radiant flux approximately 3.6× greater than the 11 mm² elements of the HIS550R series at equivalent temperature and emissivity. The gold-plated reflector (>98% reflectivity across the mid-IR) captures rear-hemisphere emission and directs it forward through the CaF₂ window, ensuring the full benefit of the large element area contributes to transmitted output. The large source étendue also improves coupling efficiency into multipass cells and large-aperture collection optics.

Patented Nanostructured High-Emissivity Surface

Emissivity exceeding 0.9 ensures near-blackbody spectral behaviour, maximising radiant efficiency and providing a spectrally smooth, predictable output across the 2–11 µm band. This simplifies bandpass filter design, inter-unit calibration, and system integration for multi-analyte instruments.

Robust TO-8 Industrial Package

The TO-8 package provides greater thermal mass and improved heat dissipation at 2.5 W drive power compared to the TO-39 platform, with a wider flange for secure mechanical mounting in instrument chassis. It is a standardised platform in high-power optoelectronics with established mounting hardware and connector options, reducing integration effort in new and existing instrument designs.

Pulsed Operation up to 4 Hz

Modulated emission at up to 4 Hz supports synchronous lock-in detection architectures. The 4 Hz limit reflects the greater thermal mass of the 40 mm² element relative to the 11 mm² elements of the HIS550R series; this bandwidth is sufficient for the majority of NDIR sensing applications. Continuous-wave operation is also supported for applications not requiring modulation.

• Broadband NDIR Gas Analysis: High-power detection of SO₂, NH₃, N₂O, CO₂, CO, CH₄, hydrocarbons, and organic compounds across the full 2–11 µm band in stationary industrial analysers where both spectral breadth and long-term sealed stability are required.
• Mid-Infrared Spectroscopy to 11 µm: Benchtop and process-line spectrometers targeting molecular fingerprint features up to 11 µm, where a high-power hermetically sealed source reduces maintenance burden and improves long-term instrument stability.
• Environmental and Emissions Monitoring: CEMS and atmospheric monitoring systems measuring SO₂, NH₃, N₂O, and other mid-infrared absorbing species in permanently installed outdoor or industrial enclosures.
• Industrial Process Gas Analysis: Fixed-point and extractive gas monitors in chemical, petrochemical, pharmaceutical, and steel manufacturing targeting species with absorption features across the 6–11 µm fingerprint region.
• Automotive and Engine Exhaust Analysis: High-precision exhaust gas analysers requiring simultaneous coverage of multiple absorption bands across 2–11 µm with the output levels needed for long-path or high-attenuation optical configurations.
• Medical and Clinical Gas Analysis: Anaesthetic agent monitors and multi-gas respiratory instruments targeting halogenated agent absorption features in the 8–11 µm region, combined with CO₂ and N₂O detection at shorter wavelengths.
• Scientific Research Instrumentation: Laboratory spectrometers, gas reference cells, and optical bench systems requiring a stable, high-power, hermetically sealed broadband source covering the 2–11 µm molecular fingerprint region.

United Spectrum Instruments (USI) is a specialist distributor and application partner for advanced photonics, infrared sensing, and scientific instrumentation in India. USI combines access to globally leading component technologies with deep domain expertise, supporting customers from initial product selection through OEM system integration and volume production supply.

Key reasons to work with United Spectrum Instruments:

• Access to internationally leading infrared emitter and photonics technologies
• Expert application support for high-power NDIR gas sensing, mid-IR spectroscopy, and industrial IR system design
• OEM consultation covering component selection, optical system design, thermal management, and production ramp
• Reliable supply for evaluation samples and production quantities
• Established partnerships with leading international photonics manufacturers
• Fast, responsive technical communication and application-focused engineering guidance