ATR Crystals and Prisms
Attenuated Total Refection (ATR) prisms operate by measuring the changes that occur in a totally reflected infrared beam when the beam comes in contact with a sample. WIth the ATR method, light penetration into the sample for total reflection is dependent on the refractive index of the prism and the sample, the wavelength and also the incidence angle. ATR is the best choice for solids, gels, pastes and liquid samples.
Advantages:
With ATR crystals there is minimum time for sampling preparation, easy cleaning and short sampling time. On top of this, the sample will not corrode the ATR prisms.
Drawbacks:
ATR is not ideal for analyzing bulk samples and the crystals must be cleaned between sampling to avoid cross-contamination. Moreover, ATR will only give you a surface measurement, and is not ideal if there is a non-homogenous sample.
The materials most commonly used are ZnSe, Ge and KRS-5 and the most common configurations are trapezoids, prism rods and paralellograms. If you are looking for something that we don’t have please contact us here.
ATR Internal Reflection Trapezoid
ATR Internal Reflection Trapezoid
The ATR Internal Reflection Trapezoid prism is designed with a trapezoidal cross-section, which provides certain advantages in spectroscopic measurements. The trapezoidal shape allows for a larger contact area between the prism and the sample, enabling a more efficient transfer of infrared light. This increased contact area helps to improve the sensitivity and accuracy of the spectroscopic analysis.
The specific dimensions of an ATR Internal Reflection Trapezoid prism can vary depending on the application. However, it typically features a trapezoidal base and angled faces that allow for efficient internal reflection and interaction with the sample.
Firebird Optics can also design these to your exact specifications on request. E-mail us at info@firebirdoptics.com.
Comparison of ATR Trapezoid to ATR Paralleogram:
Shape:
ATR Trapezoid: The ATR trapezoid prism has a trapezoidal shape with one pair of parallel sides and the other pair of non-parallel sides.
ATR Parallelogram: The ATR parallelogram prism has a parallelogram shape with two pairs of parallel sides.
Contact Area:
ATR Trapezoid: The trapezoidal shape of the prism provides a larger contact area between the prism and the sample. This allows for a more efficient transfer of infrared light and improved sensitivity in spectroscopic measurements.
ATR Parallelogram: The parallelogram shape also provides a good contact area between the prism and the sample, although it may have a slightly smaller contact area compared to the trapezoidal prism.
Internal Reflection:
ATR Trapezoid: The trapezoidal shape of the prism facilitates efficient internal reflection of light, enabling accurate analysis of the sample's absorption properties.
ATR Parallelogram: Similarly, the parallelogram shape also allows for effective internal reflection of light, leading to precise spectroscopic measurements.
Prism Handling:
ATR Trapezoid: The trapezoidal prism may offer some advantages in terms of ease of handling and alignment due to its simpler shape.
ATR Parallelogram: The parallelogram prism may require more attention to alignment and handling to ensure optimal performance.
Both the ATR trapezoid and ATR parallelogram prisms are commonly used in ATR spectroscopy, and their selection depends on the specific application requirements. The trapezoid prism offers a larger contact area, potentially enhancing sensitivity, while the parallelogram prism may provide a different prism geometry option for certain applications. Ultimately, the choice between the two would depend on the specific needs and constraints of the spectroscopic analysis being performed.
Finding the right optical window can be an exercise in choice fatigue. Let us help!