In He-Ne laser, metastable state exists in

Options

A. He
B. Ne
C. Both (1) & (2)
D. Neither He nor Ne

Answer

To solve the question regarding the metastable state in a He-Ne laser, we can break it down into the following steps:

### Step 1: Understand the He-Ne Laser Composition
The Helium-Neon (He-Ne) laser consists of two types of gas: helium (He) and neon (Ne). The laser operates based on the interaction between these two gases.

**Hint:** Consider the roles of helium and neon in the laser process.

### Step 2: Identify the Metastable State
In the context of lasers, a metastable state is an excited state of an atom or molecule that has a longer lifetime than other excited states. This allows for the population inversion necessary for laser action.

**Hint:** Recall what a metastable state is and how it differs from other excited states.

### Step 3: Analyze the Energy Levels
In the He-Ne laser, the energy levels of helium atoms are such that they can collide with neon atoms. During these collisions, helium atoms can be excited to a metastable state that has energy levels closely aligned with those of neon atoms.

**Hint:** Think about how energy levels of different atoms can interact during collisions.

### Step 4: Conclude the Source of the Metastable State
Since the metastable state is achieved through the excitation of helium atoms, we conclude that the metastable state in the He-Ne laser exists in helium. This is crucial for the laser's operation as it facilitates the necessary energy transfer to neon atoms.

**Hint:** Consider which gas is responsible for creating the conditions for laser action.

### Final Answer
In a He-Ne laser, the metastable state exists in helium.

### Summary of Steps:
1. Understand the composition of the He-Ne laser (He and Ne).
2. Identify what a metastable state is.
3. Analyze the energy levels and interactions between helium and neon.
4. Conclude that the metastable state exists in helium.