在php中按字母分解字符串

我在php中有一个字符串，如下所示：

$string = "Count the character frequency of this string";

当我使用爆炸功能时，输出显示为：

Array ( 
        [0] => Count 
        [1] => the 
        [2] => character 
        [3] => frequency 
        [4] => of 
        [5] => this 
        [6] => string 
       ) 

但上面的输出并不能让我满意，因为我想实现这样的输出：

Array ( 
    [0] => C 
    [1] => o 
    [2] => u 
    [3] => n 
    [4] => t 
    [5] => t 
    [6] => h 
    [7] => e 
    [8] => c 
    [9] => h 
    [10] => a 
    [11] => r 
    [12] => a 
    [13] => c 
   )

我想用信件把它们炸开。

我的问题是：有可能做到吗？如果是，有什么建议。提前感谢