Light.intensity

Description

The Intensity of a light is multiplied with the Light color.

The value can be between 0 and 8. This allows you to create over bright lights.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    public float duration = 1.0F;
    public Light lt;
    void Start() {
        lt = GetComponent<Light>();
    }
    void Update() {
        float phi = Time.time / duration * 2 * Mathf.PI;
        float amplitude = Mathf.Cos(phi) * 0.5F + 0.5F;
        lt.intensity = amplitude;
    }
}