- **Cathetometer:** It is used for measuring linear distances or heights with precision. It doesn't measure infrared radiation.

- **Pyrheliometer:** Measures direct beam solar irradiance. It's used in solar studies but not specifically for infrared radiation.

- **Phenograph:** There's no standard instrument called phenograph related to radiation measurement. It may be a mistake or a hypothetical name.

- **Bolometer: ✅** A bolometer is designed to measure the power of incident electromagnetic radiation, including infrared radiation. It is highly sensitive to changes in temperature caused by absorbed radiation.

🔍 **Highlighted Answer: Bolometer**
Since the bolometer measures infrared radiation, **YOUR ANSWER IS RIGHT**.