linq to json

IEnumerable<Employee> empJson = from emp in employees 
where emp.Department == "IT Department" 
select emp; 
DataContractJsonSerializer ser = 
new DataContractJsonSerializer(typeof(IEnumerable<Employee>)); 
MemoryStream ms = new MemoryStream(); 
ser.WriteObject(ms, empJson); 
string json = Encoding.Default.GetString(ms.ToArray()); 
ms.Close(); 
Response.Write(json);